A bag of clothes thought to be those of the victim also was found nearby.
Police are looking for reports of any people reported missing in recent days.
An initial inspection, conducted by officers from Samran Rat police station and forensic doctors, found the man had suffered up to 10 knife wounds to his body, acting city police chief Saint Maha Thaworn said.
Police say there were wounds near his head, left arm, armpit and leg, but those near his neck are believed to have caused his death.
Pol Lt Gen Sanit said the officers could not identify his nationality at this stage, though a quick inspection suggested he was an Asian male.