The work aims to analyze erosive wear caused by solid particles on orifice plate flowmeter during transmission of liquid/solid fluid. DPM model based on Euler-Lagrangian algorithm was used to numerically simulate erosion of the liquid/solid orifice plate flowmeter in liquid/solid fluid metering process. Areas in which the orifice plate flowmeter was prone to erosive wear in liquid/solid fluid metering process were predicted. The effects of inlet liquid velocity and solid particle size (when equal number of particles struck the wall surface) on difform orifice plate were explored. Erosive wear rate on the difform orifice plate during transmission of liquid/solid fluid was compared. Severe liquid/solid erosion failure might appear in such pipe sections subject to sudden contraction on the flowmeter. The maximum erosion rate increased with the increase of inlet liquid velocity. When mass flow rate of solid particles was equal, the maximum erosion rate decreased with the increase of particle size. When an equal number of solid particles of different particle size flowed through the orifice plate in unit time, erosion wear rate increased with the increase of solid particle size. For liquid/solid fluid flow metering process, the solid particles caused less erosive wear on convex orifice plate. Large particles will cause serious erosive wear on the orifice plate, hence it should be strictly noted in the orifice plate metering process. In case of plenty of large particles in the fluid, use of convex orifice plate flowmeter can effectively improve erosive wear.