In order to clarify the effect of rubber powder contents on mechanical properties of engineered cementitious composites (ECC), so as to provide theoretical basis for preparation of fiber reinforced cementitious composite, the effects of different rubber powder contents (0~ 30%) on the mechanical properties of ECC are analyzed through compression tests, uniaxial tensile tests, and bending tests, including compressive strength, ultimate tensile stress, ultimate tensile strain, and bending displacement. The research shows that: 1) The increase in rubber powder content will reduce the compressive strength of ECC. 2) The incorporation of rubber powder helps to improve the ductility of domestic ECC. PVA-ECC with rubber powder shows obvious strain hardening and multiple crack propagation phenomena under tension, and its tensile strain is significantly improved. The incorporation of rubber powder improves the flexural toughness of PVA-ECC, which is manifested by the continuous increase of bending displacement. 3) When the rubber powder content is 10% , ECC has the best mechanical properties. This study explores the influence law of different rubber powder contents on the mechanical properties of ECC, which can provide theoretical basis and practical guidance for the preparation of fiber-reinforced cement-based composites.