In the paper,a new stochastic constitutive model was proposed,which can demonstrate the rendom damage evolution law of concrete material under Uni-axial tension stress.Based on the Acoustics Emission character during the strain-stress history test,a traditional spring model was renewed to explain the damage mechanism.In the model,by establishing the relationship of the distribute character and AE energy emission rate ,the strain stochastic failure field(SSFF) is formed.So the course of damage development is simulated with the SSFF.Within the frame of energy equivalence law,the critical valve strain which began to be unstable and again to stable were concluded in mean level,so the macro strain-stress history curve was redisplayed by the failure mechanism model.The reason for brittleness for concrete material can also be explained by comparing the ideal representative element with the general element.In order to testify the validity of the model,the calculated result was compared with the test result.It shows that the model forecasted strength is quite near the test value.And the model can also forecast the scatters of concrete in probability means.