In order to obtain the CA mortar that can satisfy high-speed railway construction,CA mortar with different proportion was prepared.Through studying strength of CA mortar and Observating its microstructure by scan electron microscopy,the strength and its development of CA mortar was studied by changing sand gradation,the ratio of sand to cement and the ratio of asphalt emulsion to cement.Results show that using combination of two kinds of sand with particle size of 0.15-0.3 mm and 0.3-0.6 mm in CA mortar can reduce the material separation greatly while posing little effect on the 28 d compressive strength of high strength CA mortar.With the increment of m(S)/m(C),the 1 d compressive strength of high strength CA mortar increases but the 28 d compressive strength doesn’t change initially until reaching the critical point 1.4,which drags huge decline for it.The compressive strength of high strength CA mortar of different ages are significantly declining with the increment of m(A)/m(C).Selecting the appropriate size sand,m(S)/m(C) and m(A)/m(C) is the premise to obtain the CA mortar that can satisfy high-speed railway construction.