Effects of chromium addition on microstructure, two-body abrasive wear behavior of Fe–B cast alloy and fracture toughness of boride were investigated. The results indicate the solidification microstructure of Fe–3.0 wt% B alloy consists of ferrite, pearlite and eutectic boride. After quenching, the alloy microstructure is composed of martensite and boride. With Cr addition increasing, microhardness of matrix and boride has tiny fluctuation; fracture toughness of M₂B increases first reaching the maximum (4.704 MPa m^1/2) at 2.0 wt% and then decreases; two-body wear resistance increases first and then decreases under contact loads of 15 N, 35 N and 55 N, possessing similar variation trend with fracture toughness of M₂B. This indicates the toughness of M₂B has directly positive influence on wear resistance of Fe–3.0 wt% B cast alloy.