The attempted abduction happened at about 08:00 GMT while the boy was walking to school along North Road, Bourne.
The offender is described as 6ft and white, with short spiked brown hair and tattoo on his neck.
Officers are warning the public to not let children go out alone.
Det Insp Pete Grayson, from Lincolnshire Police, said the boy was very frightened by the incident.
He urged anyone with information to contact the force.

According to reports, he was a member of the firm's UK team.
He was understood to have been attending the Cannes Lions event, an annual gathering of people in the advertising and marketing industry.
In a statement, Google said: "We lost a loved and respected member of our team. We are deeply saddened and our thoughts are with his family and friends."
No further details about the employee have been made public out of respect for his family.

The pair collided while attempting to take a catch during Sunday's T20 Blast game with Sussex at Arundel.
The match was abandoned after ambulances took them from the field.
Australia international Henriques, 28, broke his jaw in three places, while Burns, 24, had cuts around his left eye that required stitches.
Surrey announced on Twitter on Monday that the pair were "in decent shape".
And a further update from the club on Twitter 24 hours later read: "More good news on the lads - Moises has now been released from hospital and will see a dental specialist tomorrow. He's improving slowly!"
Burns, meanwhile, tweeted his thanks "to all the medical staff" who treated the pair and his hope that his club colleague "keeps progressing well."
Team-mate Kevin Pietersen, who was in the field at the time of the collision, said the incident deeply affected the team.
"I kept thinking one of the guys will call. Then you think one will stop but then bang, bang. It was absolutely sickening," Pietersen told the Daily Telegraph.
"When those guys went down and did not move it hit some of our guys very hard.
"It was the right decision to abandon the match. We had lost two of our players, a lot of players were crying in the dressing room and it is only a game of cricket."
Director of cricket Alec Stewart also posted a picture on Twitter of Burns smiling in his hospital bed.
Henriques, who has played three Tests, six one-day internationals and four T20 games for Australia, joined Surrey in April as an overseas player for their T20 Blast campaign.
Surrey-born Burns, a left-handed batsman and occasional wicketkeeper, made his first-class debut for the county in 2012.
Surrey's County Championship game with Glamorgan began as scheduled on Monday.

Kneen, 28, won both Superbike events on his way to collecting the man-of-the-meeting award two years ago, and will ride for the Mar-Train Yamaha outfit.
Ryan Farquhar takes in the 'big bike' events on his BMW Superstock and the Supertwins class on his KMR Kawasaki.
Malachi-Mitchell Thomas competes after taking a treble at the Mid Antrim 150.
The Bolton rider is joined in the Cookstown BE Racing team by Dubliner Derek Sheils, who won the feature event at Mid Antrim on 2 April on his 1000cc Suzuki.
Farquhar struggled with the stability and electronics on his Superstock machine at Mid Antrim but emerged the victor in the Supertwins and won the opening Superbike race over the 5.3-mile Tandragee circuit last year.
William Dunlop is set to campaign his Supersport 600cc Yamaha at the County Armagh meeting, with Republic of Ireland competitors Derek Sheils and Derek McGee also in the mix.
The meeting features a nine-race programme, with practicing on Friday and racing on Saturday.
Police are hunting a man who tried to force an 11-year-old boy into the back of a black van in a Lincolnshire market town.
[NEXT_CONCEPT]
A Google executive has been killed in an accident in Cannes, France, the search company has confirmed.
[NEXT_CONCEPT]
Moises Henriques has been released from hospital following the on-field collision with Surrey team-mate Rory Burns that left him with a broken jaw.
[NEXT_CONCEPT]
Manxman Dan Kneen will be out to repeat the form he showed on his debut in 2014 when he takes part in this weekend's Tandragee 100 road races.