The load（ working condition） coefficient is one of the important original inputs in the design of chain transmission system,it is directly related to design variables of the chain bearing capacity,especially for the timing silent chain system,the chain plate thickness or number are all related to it. Through a engine timing chain system design,ignoring the torsional vibration and engine cylinder to work,the load characteristics of the timing silent chain system are analyzed qualitatively. By using the cylinder head anti drag system test bench,through static and dynamic load torque test,the load coefficient and the method of determining under different speed conditions of the timing silent chain system are proposed,which is of great reference value to the design of the multi axis and high speed silent chain system.