Abstract: The acoustic emission (AE) behavior in the process of rock fracture is not only closely related to the rock types but also to the load and microfracture progress. Thus, AE wave spectrum obtained from loaded rock specimen contains a great amount of information concerning microfracture of rock.The microfracture mechanism of rock under compressive-shear loading is studied using wave-spectrum analysis in this paper. the relation between wave-specturm behavior at different loading stages and mechanical response of rock and critical crack propagation is discussed. The results show that wave-spectrum parameters are more sensitive to microfracture of rock than to load itself, which is quite significant for solving engineering problems, such as safty estimation and rock burst prediction in mining process and slope stability analysis in geological engineering.