The selfproduced grazingexit Xray fluorescence platform is proved with high repetition and stability, and the design of experimental arrangement is reasonable, by studying the repetition of grazingexit Xray fluorescence experiment on GaAs (100) polishing wafer under the same condition, and comparing with experimental results with conventional Xray source and synchrotron light source. The experimental curve fits quite well with the theoretical one, which indicates that the method using the critical angle of total reflection of monocrystal to calibrate the grazingexit angle is feasible. Practical divergent angle is evaluated by the derivative of the standard wafer's grazingexit Xray fluorescence curve.