Abstract: The microstructure, performance and three body abrasive wear characteristics of the cast medium carbon high boron steels were studed by optical microscopy, scanning electron microscopy (SEM) and self-made three body abrasive wear tester. The results show that when the boron content increased, volume fraction of hard-phas, hardness and wear resistance of the test steel increased, but impact toughness reduced. The increase of hard-phase quantity and size was good to resist abrasive cutting and furrow deformation. The wear of matrix was mainly attributed to micro-cutting and plastic deformation, and the hard-phase showed fracture wear mechanism. Small wear rate was given in low load as a lot of deformed matrix cumulated, but fracture of the boron carbon compounds accelerated in high load leading to the rapid increase of wear rate.