The work aims to investigate the effect laws of ultrasonic assistance on mechanical properties of laser cladding Al2O3-ZrO2 ceramic coating. COMSOL Multiphysics was used to explore the change of flow field with the ultrasonic assistance. In this method, ultrasonic waves were directly applied on the micro-zone of molten pool. The effect of ultrasonic assistance on the cross-sectional morphology, microstructure, element distribution, microhardness and friction and wear properties were investigated through experiments. The simulation results showed that the size of the eddy current in the cross-section of the molten pool was symmetric and the velocity of flow was slow without the ultrasonic assistance. Under the assistance of ultrasound, the sound velocity of the cross section of the molten pool changed instantaneously and the velocity of fluid in the molten pool increased. Experimental results indicated that the cross section morphology of the cladding layer changed with the ultrasonic assistance, but the cracks in the cladding layer were inhibited. The grain size of cladding layer was refined with the ultrasonic assistance. When the laser power was 1700 W, the grain size was the smallest and relatively denser. The element distribution in the cladding layer was more uniform with the ultrasonic assistance, and the interface effect was reduced. The mechanical properties of the cladding layer were improved with the ultrasonic assistance. When the laser power was 1700 W, the average microhardness value of the cladding layer was 979.4HV0.2. Under the same laser power, the cladding layer had a larger average microhardness value with the ultrasonic assistance. The friction coefficient and fluctuation amplitude of cladding layer were small with the ultrasonic assistance. The friction coefficient was the smallest (about 0.329) when the laser power was 1700 W, and the fluctuation was relatively stable. Ultrasonic wave can be directly introduced into the micro-zone of the molten pool to improve the fluidity of the molten pool, refine the grain, homogenize the element distribution and improve the mechanical properties of the cladding layer.