The embodiments of the invention disclose a nuclear power plant interference testing method and an apparatus to solve the problems in the current nuclear power plant interference testing that the testing efficiency is low and the testing result is not so trustful. The method proposed by the embodiments of the invention comprises: determining the to-be-tested targeted wireless communication system and the devices under interference; obtaining the frequency band of the testing signal during the testing of the targeted wireless communication system; obtaining the initial signal power of the targeted wireless communication system as the testing signal power during the testing; controlling the targeted wireless communication system to transmit the interfering signals for various signal frequencies respectively according to the testing signal power; according to the working states of the devices under interference, determining the scope of the first frequency band of the interfered devices under the influences of the interfering signals; if the scope value of the first frequency band is not zero, then, using the preset first power to reduce the testing signal power in a stepping manner and returning to the step of executing the emission of interfering signals; and if the scope value is zero, then, determining that the current testing signal power is the interference-free signal power threshold.