The invention discloses a synchronous wheel structure. The synchronous wheel structure comprises two wheel pieces which are arranged in parallel, a transmission cavity is formed between the two wheelpieces, one or more adjustment grooves are formed around the wheel pieces for a circle, a transmission gear is arranged between every two adjustment grooves of the two wheel pieces, and the two ends of each transmission gear are buckled into the corresponding adjustment grooves respectively; connection shaft sleeves are embedded into extension ends of the two sides of the bottom of each transmission gear respectively, a shaft hole is formed in the middle of each connection shaft sleeve, an adjustment bolt is inserted into each shaft hole, head parts of the adjustment bolts are fixedly welded to the shaft holes, the bottoms of the connection shaft sleeves are embedded in the transmission gears, and the other ends of the connection shaft sleeves protrude out of the transmission gears. The synchronous wheel structure is simple, and the positions of the transmission gears in the adjustment grooves can be adjusted so that synchronous belts different in transmission ratio can be replaced, more flexible installation is achieved, the protruding adjustment bolts can be used for installing transmission shafts, and the problems of inconvenient disassembly and wearing since the transmission shafts are directly inserted into the synchronous wheels in traditional structures are solved.