Using orifice flowmeter numerical simulation results it finds that the orifice plate flow characteristics of poor reasons.In order to improve the orifice outflow characteristics,the author designed three kinds of different inlet cone angle conical orifice.Tapered orifice discharge coefficient increases with the entrance cone angle decreases in simulation results,but the increasing trend decreasing.Finally,design an actual cutting pieces based on the simulation results.Analysis of the reasons of different discharge coefficient between simulation results and experimental results,and apply this improvement orifice plate to actual flow measurement.