Abstract: The concrete mechanical properties of 1 d-7 d have very important effects on the durability of concrete structure. In order to explore the early mechanical property law of concrete， the mechanical properties of concrete in the first seven days are tested on the basis of four proportions. The research findings and conclusions are as follows： (1) the growth rate of cubic compressive strength， axial tensile strength， splitting tensile strength and ultimate tensile strain of concrete in the first three days is higher than the growth rate in 3 d~7d； (2) the axial tensile strength of concrete is greater than its splitting tensile strength in the first seven days； and (3) the pressure ratio of concrete based on splitting tensile strength and the pressure ratio of concrete based on axial tensile strength both tend to decrease firstly and then increase slowly， but the pressure ratio of concrete based on splitting tensile strength is greater than the pressure ratio of concrete based on axial tensile strength.