In order to reduce the motion unevenness of the conveyor chain,a new kind of double- pitch silent chain is proposed and used in conveyor to replace the traditional double- pitch roller chain. The main design parameters of the chain plate is given,the double- pitch silent conveyor chain system and double pitch roller conveyor chain system of the virtual prototype model are created,and the simulation comparison experiment of the motion unevenness of this two systems are carried out. The analysis results show that,under the same condition,compared with double- pitch roller chain,the tension side lateral fluctuate value,unevenness of horizontal velocity and unevenness of driven sprocket angular velocity of double- pitch silent chain are respectively reduced 24. 18%,45. 61% and 23. 13%. Therefore,it can be deduced that the double- pitch silent chain motion unevenness is smaller than double- pitch roller chain distinctly.