The surface of the diesel connecting rod big end bearing bush has waviness during the machining process,and the surface waviness seriously affects the lubrication performance of the bearing contact surface.Aimed at this problem,an elasto-hydrodynamic model of the connecting rod group considering the surface waviness was established,and the influence of different amplitude,order,and number of waviness on the lubrication characteristics of connecting rod big end bearing was analyzed.It is found that with the increase of the amplitude,order,and number of waviness,the minimum oil film thickness generally increases and then decreases,and the total friction power consumption first decreases and then increases,indicating that a reasonable distribution of surface waviness has a positive impact on bearing performance and can improve the lubrication performance of bearings.Based on the Box-Behnken design and response surface method,the lubrication characteristics of diesel connecting rod big-end bearings were studied.The amplitude,order and number of the bearing surface waviness were used as optimization variables,and the minimum oil thickness and total friction power consumption were optimized.The target was optimized by response surface and combined with Non-dominated Sorting Genetic Algorithm-Ⅱ(NSGA-Ⅱ).The results show that different bearing bush waviness has a great influence on the lubrication characteristics of the connecting rod big end bearing.Compared with the smooth surface of the bush,the minimum oil film thickness after optimization is increased by 11%,the total friction power consumption is reduced by 14%.