The invention relates to the field of the indoor soil testing of civil engineering, in particular to a cement soil direct-shear test specimen preparation device capable of carrying out gradation loading. The device comprises a pressure application mechanism, a sample bearing mechanism, a supporting mechanism and a cutting mechanism, wherein the sample bearing mechanism is installed on the supporting mechanism; the pressure application mechanism can be cooperated with the sample bearing mechanism to apply pressure to cement soil to obtain a master sample; and the master sample is pushed into the cutting mechanism from the sample bearing mechanism to be cut into a plurality of standard test specimens. After the above scheme is adopted, a plurality of test specimens can be prepared in one time, an artificial error between the test specimens is eliminated, the true stress condition of the cement soil in a construction site can be simulated through a gradation loading specimen preparation process, and a test result is more similar to a field situation.