Based on the Archard wear model, a mathematical wear rate model in the course of friction between brush and conducting ring was set up. A friction and wear test bench for conducting ring was built， the friction and wear performance of electro-contact of silver - based composite brush is verified experimentally. We can conclude that a large contact pressure makes micro-convexs on the surface to the state of plastic deformation and forming abrasive particles more easily.The carrying current forms corrugated abrasion marks on the surface of the brush material and produces powder abrasive particles.The wear rate increases first and then decreases at the beginning of wear due to the small contact area and the hardening effect of surface processing.The wear rate model is modified so that it is more accurate to predict the wear rate of silver base composite brush.This study provides theoretical guidance and experimental basis for further research and development of silver-based composite brush.