The driver asked the man to stop, but the verbal harassment continued.
Then, while stopped in the area of Main Street and Broadway, the suspect approached the driver and spit at him.
"He then took hold of the driver and pulled him out of the bus and began assaulting him," police said.
The driver was able to push the suspect away, get back on the bus and call police.
The suspect ran away.
The driver was taken to hospital, treated and released. Police are looking for a man in his twenties.