The shielding effectiveness is a key index to measure the performance of electromagnetic protective materials However, the traditional shielding effectiveness testing methods exist many losses, there by the experimental data varying under different test conditions. This paper aims to provide a novel NV-center based optical high-resolution shielding performance testing method, a method that may directly provide the distribution of the electromagnetic field on the surface of the electromagnetic shielding material. This method was used to test the shielding performance of two different electromagnetic shielding materials, and comparison with the surface scan method has proved the feasibility and reliability of the optical high-resolution test method, providing a new idea for testing the effectiveness of electromagnetic shielding materials more accurately and effectively.