Abstract: Based on an analysis and study on the availa ble coal plough theory at home and abroad,in combination with the thin seam mining status in China,the paper analyzed the axle horizontel vibration.polygon effectof the chains pretension on the chains and other factors during the actual operation process of the coal plough. A mulibody dynanics model of the coal plough was built and the factors affected to the reliability of the plough chains were considered.Wwith a Malab applied to the simulation analysis,the time process of the tension at the front and rear of the plough chains and the runingspeed of the plough chains were obtained . Thus the factors affected to the chain service life of the plough.The related pretension of the plough chain and the random coal wall action role would cause serious ifluences to the fatigue life of the plough chains and the polygon efict of spocket wheal culdcause relative light influences.Finally,the paper provided the certain plan to improve the service life of the plough chains.