The chatter marks are analyzed and researched, which appeared in driving wheels of espicychoid spiral bevel gear in dry cutting process. By actual machining testing and procedure monitoring purposefully, it was found that the appearance of chatter marks were intimately associated with the tightened clamping fixture and variable positioning caused by heat in finishing process. An optimization design was proposed for modifying the clamping fixture design to eliminate or decrease the influence of heat by analysis. The modified clamping fixture is tested and the effect is good.