The concrete rebound values were calibrated at 7 different load degrees, i.e. 5,10,15,20,25,30 and 40kN. The concrete strength grade was C20,C30,C40,C50,and specimen size was 100mm×100mm×300mm. The relationship between rebound value and load was researched. Results show that the critical value of pressure is about 0.25kN/cm2 when rebound values are stable. Comparing tested value with inspecting technical specification, it is found that the rebound value could not be measured correctly at the load in accordance with currently used technical specification. The results could provide a new basis for revised edition of rebound inspecting technical specification.