The invention discloses a method and system for testing a polarization code forming rate of a power quantum security communication system. The method comprises the steps of: presetting various types of test cases related to power grid environment parameters; checking a test environment and a test sample, and after receiving a test request of a user, according to the test request, selecting a target test case; and controlling the power quantum security communication system to generate a corresponding quantum key by the test sample in the target test case so as to carry out quantum key encryption transmission of power service information, and recording a test result. By setting various types of test cases, the method aims to solve difficult problems of complexity for power communication networking, large space span, influence of electromagnetic radiation, large interference of natural environment factors and the like and develop simulation on a quantum signal performance testing work of the quantum security communication system in a power grid environment, so that testing on an operation condition and various performance indexes of the quantum security communication system in the power grid environment and verification on feasibility of applying the quantum security communication system to a power grid service are implemented.