A repo man in Tennessee's proving you gotta have a lot of brains to do the job ... 'cause the person whose car you're repossessing may try to crush them out of you.

Check out the incident that went down in the Memphis area Wednesday -- video captures the repo man pulling up to the front of a red 2011 Ford Focus to hook it up and tow it away.

Another man, in a green shirt, comes streaking in from the side ... dashing over to the driver's door, wrenching it open and starting the car.

While this is happening, the man trying to repossess the car makes a dangerous choice ... putting his head and torso under the car to lock the chain hook on.

That's when the driver slams it into full reverse ... running over the repo man's head, causing him to scream in pain.

The driver's not deterred by this speed bump ... and ultimately drives off with the car -- after bumping into a wall and driving through a bush.

The Memphis Police Dept. tells TMZ ... the repo man sustained abrasions on his head and was experiencing arm pain ... and he "had to be shook in order to keep him awake." He was hospitalized in non-critical condition.

Police said a woman seen in the video told the suspect to "hurry up!" ... but she was not at the scene when officers arrived. Cops knocked on the door of the male driver suspect's cabana but received no answer.

The victim posted his injuries online afterward ... showing him scraped up and wearing a neck brace.