The flow characteristics of super-high pressure pneumatic fueling valve, a critical component of the fueling system, were detailed investigated by experimental way. The problems of large driving power need，slow response and high pressure gas leakage of super-high pressure pneumatic fueling valve, were solved by using pneumatic lever rule and self-acting sealing structure. A two-stage valve that used a pilot solenoid valve, moderate pressure and low flux, to control a high pressure and large flow-rate poppet valve is developed. A test apparatus with the affiliated measurement system for testing the flow characteristics of the pneumatic fueling valve orifice were introduced. A simplified model of the flow channel of fueling valve for different valve lift was obtained. Experimental study on the flow characteristics of the pneumatic fueling valve with different orifice throttling area was carried out under the condition that the pressure is higher than 10MPa. The results show that the back pressure growth rate of tank and the lift of valve rod have great influences on the flow characteristic of valve orifice. When valve lift is relative taller, the gas channel could be simplified as two-stage orifices in series, the flow characteristics are in accordance with that of ideal converging nozzle, and the critical pressure ratio is 0.5. When valve lift is relatively lower, the gas channel can be simplified as three-stage orifices in series, shows different flow characteristics, and the critical pressure ratio is 0.3. Increasing the valve lift and the injecting pressure is the most effective solution to enhance both the transient mass flow-rate and the discharge coefficient.