Cutter is a core component of cutter suction dredger，and it is very expensive to study the excavation performance of cutter through field test.To solve the problem of meeting the suitable soil quality in the real ship test difficultly，a method to characterize the excavation performance of the cutter by excavation test and numerical simulation in the laboratory is proposed.Scale model of 2 000 kW power cutter and rock model with different uniaxial compressive strength are made.Model tests of cutter cutting rock with different cutting thickness and stepping distance are carried out in the laboratory，and 1:1 scale cutter numerical model and rock model are established.The cutting process of 2 000 kW cutter is simulated by unit deletion method，and the cutting processes with output of 240 m3/h and 500 m3/h are simulated respectively，and the cutting power and the cutting power of cutter are analyzed.The results show that when the excavation output is 240 m3/h，the maximum power is 1 884 kW and the average power is 1 088 kW，which meets the design requirements.