Leigh Nairn said his drone was badly damaged in the incident at Binnu, 550km (340 miles) north of Perth.
The drone, used to monitor barley-seeding equipment on his property, was sent off to be repaired.
He said he was "100% lucky" that the drone managed to capture an image of the bird as it swooped.
"That's the only photo I have of it," he said.
"I'm not sure where it came from, but I was obviously in the wrong spot and [it] wanted to let me know that."
The eagle flew off unscathed, he said.
He said the species, Australia's largest bird of prey, sometimes attacked lambs on the 7,500-acre (3,000-hectare) farm.
Despite being a nuisance the birds were "fantastic to look at", he said.
"They are protected, as they should be, but they do give you a lot of trouble during lambing season," Mr Nairn told the BBC.
It is not uncommon for the species to take down drones. In November, an Australian mining company lost nine surveying drones to bird attacks at a total cost of more than A$100,000 (Â£60,000; $75,000).
But in "a low-tech solution to a high-tech problem", Dutch police have trained eagles to take down unauthorised drones.
A farmer in Western Australia has described the moment a wedge-tailed eagle attacked his drone and sent it crashing to the ground.