Aiming at the rotating assembly of axial piston pump,a finite element model of single disk cantilever flexible rotor with transverse breathing crack was established.The numerical integration method was used to simulate,the time history,axis trajectory and frequency spectrum of the rotor system were obtained,and the effects of crack depth and crack position on the vibration characteristics of the rotor were analyzed.The results show that when the transverse crack is located at bearing No2,the amplitudes of the second harmonic generation and the third harmonic generation of the rotor increase with the increase of the crack depth,and the axis trajectory tends to move inward when the rotor speed is near the critical speed of 1/2 and 1/3;when the crack is near the rigid disk,it has less influence on the rotor axis trajectory,frequency amplitude,and the axis trajectory has the characteristic of moving outward.