Piezoelectric pumps are applied in cooling systems of microelectronic devices because of their small size. However, cooling efficiency is limited by low flow rate. A Straight arm wheeled check valve made of silica gel was proposed, which can improve flow rate of piezoelectric pump, solve the influence of glue aging on the sealing ability of a wheeled check valve and reduce the size of piezoelectric pump. This paper discusses the influence of valve arm number (N=2, 3 and 4), valve arm width (W=1.0, 1.2 and 1.4mm) and valve thickness (T=0.6, 0.8 and 1.0mm) on flow rate characteristics of piezoelectric pumps. When valve opening rises, the flow rate increases. The simulation results show that valves with 2 valve arms, 0.6mm valve thickness and 1.0mm valve arm width have maximum valve opening. Experimental results show that piezoelectric pumps with different valve parameters have different optimal frequencies. In addition, maximum flow rate is 431.6mL/min at 220V and 70Hz. This paper provides a reference for the application of piezoelectric pump in cooling system.