The 57-year-old was approached by another man on a footpath in Ferguslie at 07:55.
He threatened his victim with a knife and demanded he hand over his money and possessions.
Police said that when the man refused, the suspect ran off in the direction of Abbey Nursery and Millarston Park.
He was about 6ft tall and was wearing a home-made balaclava.
Officers said his blue beanie hat, which had white stripes at the bottom, was pulled down over his face and slits had been cut for his eyes.
Det Con Aileen Cunningham said: "I would like to speak to anyone who was in the Ferguslie area this morning and saw anyone acting suspiciously.
"In particular, I would like to trace the male driver of an old silver style Polo which was seen driving in the area heading towards Paisley around the time of the incident.
"We believe the driver may have witnessed what happened so I would ask him to get in touch."
Police have launched an investigation after a man was threatened with a knife in Paisley.