Elastic modulus is an important mechanical parameter of concrete. Static stressed elastic modulus test is made, so as to study the factors influencing the elastic modulus of C50 concrete. Conclusions drawn are as follows: water binder ratio is the main factor that influences the compressive strength of concrete; the type of coarse aggregate is the main factor that influences the elastic modulus of concrete; the elastic modulus of concrete that is prepared by granite aggregates is low; the elastic modulus of C50 concrete can be improved when some basalt aggregates are mixed.