At present,the research of vortex shedder focused on shedder shape and size , but in the field of complex environmental conditions, the location of shedder is not fixed, there will have a certain amount of error.For a good analysis of problems about changed signal strength with spectrum brought by misalignment of the vortex shedder, the simulation model is built based on the actual physical vortex flowmeter size with the shape called triangular prism of vortex shedder by using Ansys+Workbench+FLUENT software. Then divided the simulation model into grids and get the result. After comparing the frequency of lift force with drag force, concluded that the Resistance frequency is as twice as the Lift frequency . The simulator result shows that use FLUENT to numerical simulation is feasible. Compare and analysis the signal strength with spectrum distribution at low, medium and high velocity by changing the angle between the surface of the pipe crosssection and closure. Thus we obtains the relationship between the angle of the signal strength: The effect on the signal strength is small when angle in the range of 1 degree to 7 degrees , and larger impact more than 7 degrees.