Abstract: As a common electric connection mode on the PCB, the coupling of the non parallel microstrip lines is complex and difficult to predict due to the angle change. It has not been given enough attention. Based on this situation, the coupled model of non parallel microstrip lines is established and the model's validity is verified. The crosstalk curve evolution from the parallel to the non-parallel is studied in detail by using the finite element method (FEM) . The effectiveness for using stripe protection with width change to suppress crosstalk of the non-parallel microstrip lines is validated. In order to ensure the attenuation effect and the cost saving, use the short stripe protection and change the starting position to suppress crosstalk. The dependence of the grounding hole radius for the crosstalk are investigated, the difference　conclusion from previous results in the literature is got. Through a detailed analysis and then the corresponding rule's summary, the theoretical guidance for the optimization design of non-parallel microstrip lines and the stripe protection are provided.