Pressure rise is one of the key operation characteristics of a wave rotor combustor (WRC), which would affect the power performance of the propulsion system based on WRC. To find out the pressure rise characteristics of WRC, a simplified test system of WRC was established, which is a single-channel multiple-cycle WRC with a rotating inlet/outlet port. The effects of the filling speed of air-fuel mixture, the rotating speed of inlet/outlet port, and the equivalence ratio of combustible air-fuel mixture on pressure rise characteristics of WRC are presented. The pressure rise is derived from the flow stagnation of filling combustible air-fuel mixture and the constant volume combustion in channel. With the rotating speed of inlet/outlet port increasing, the pressure rise significantly improves and the maximum average pressure is 6.3 atm. When the rotating speed of inlet/outlet port is constant, there is a suitable filling speed of air-fuel mixture and an optimum equivalence ratio for combustible air-fuel mixture. With the increasing of the rotating speed of inlet/outlet port, the suitable filling speed of combustible air-fuel mixture also increases and the operating range of the equivalence ratio of combustible air-fuel mixture becomes narrow.