Abstract: The hardening properties of carbide (WC)-reinforced steel matrix composites after austenization between 980℃~1240℃ have been investigated. It has been found that the tested material has a remarkable hardening effect, 68HRC, and tempering resistance.The present work has measured the micro-hardness (HV_0.05) of the massive hard phase, WC aggregated and matrix in the material microstructures and studied the relationship between the micro-hardness (HV_0.05) and macro-hardness(HRC). From materialogy and alloy electron theory, the highly hardening effect comes from the contributions of the strong martensite matrix containing carbon structure units with W, Mo, etc and numerous hard phases.