In view of the problems of large output and serious environmental pollution of granite waste powder (GWP), the activity of GWP at different ball milling times (0, 10, 20 and 30 min) and the effect of equal mass substitution (0%, 10%, 20% and 30%) on the macro and micro properties of GWP mortar were investigated. The experimental results show that the GWP activity after ball milling for 30 min is high, reaching 72.98%. As the GWP replacement rate increases from 10% to 30%, the flexural strength, compressive strength and dynamic elastic modulus of the mortar decrease by 6.31%~23.94%, 3.02%~26.11% and 5.35%~24.29%, respectively. The carbonization depth and chloride ion permeability coefficient of the mortar increase by 20.43%~81.40% and 2.31%~20.61%, respectively. The addition of GWP makes the mortar microstructure deteriorate, cracks and holes increase, and harmful holes increase. Based on the established relationship between the GWP replacement rate and the strength, durability of the mortar, the optimal replacement rate of GWP is from 12.37% to 21.74%, in which the performance of GWP mortar is still close to that of the benchmark group although there is a certain degree of decrease. Comparing the energy consumption and economic cost of GWP mortar with different substitution rates, each additional 10% of GWP used to prepare unit volume of mortar can reduce energy consumption by 107.08 MJ and economic cost by 46.01 yuan.