The invention discloses a relay protection testing device applied to an electronic current transformer and a protection device therefor. The relay protection testing device comprises a frequency converter, a small signal generator, a signal monitor, a change over switch and aviation plugs, wherein an input end of the frequency converter is connected with an alternating current power source, an output end of the frequency converter is connected with an input end of the small signal generator, an output end of the small signal generator is connected with an input end of the signal monitor, an output end of the signal monitor is connected with an input end of the change over switch, and an output end of the change over switch is used for outputting small analog signals to the electronic current transformer or an electronic current transformer protection device via the aviation plugs. In the relay protection testing device, the small signal generator is used for directly generating the small analog signals that are high in precision, magnitude of small analog signal values can be randomly adjusted as needed, the aviation plugs corresponding to the electronic CT and the protection device for the same are used for transmitting and detecting the small analog signals, and the electronic CT and the protection device for the same can be verified conveniently.