The elastohydrodynamic lubrication(EHL) contact with fixed and varying loads between the pin and the bush in the chain drive was analyzed by numerical simulation,and the bush does reciprocating motion relative to the pin. The load was assumed to be constant or time-varying over the motion during the process of meshing in and out of the chain wheel. The characteristics of EHL oil film in line contact in reciprocating motion with a constant load condition and time- varying load condition were compared. The influence of different stroke length on the characteristics of EHL under varying load was analyzed. The results show that the varying load has a great influence on the pressure and thickness distributions of the oil film. The oil film pressure is increased sharply and the film thickness is decreased with the increase of the varying load,but the effect of loading mode is trivial on the friction coefficient. Under the same loading mode,with the increase of stroke length,the oil film pressure is decreased,the center film thickness and the minimum film thickness are increased obviously.