The invention discloses a testing signal generating device for an intelligent substation testing system. The testing signal generating device comprises a control module and at least one path of testing signal generating circuit, wherein each path of testing signal generating circuit comprises a digital display scope (DDS), an oscillation circuit, a filter module and a power amplify module. The DDS is used for outputting sine signals with output frequency and phase adjustable according to control signals of the control module; the oscillation circuit is connected onto an input terminal of the DDS and used for providing clock signals required by working of the DDS; the filter module is connected with the DDS for performing filter treatment on the sine signals output by the DDS to filter noise and scattered signals; and the power amplify module is connected with the filter module for amplifying power of the sine signals performed with the filtering. The testing signal generating device can fully utilize the advantages of low power consumption, high resolution, fast transformation and the like of the DDS, provides testing signals for various testing devices and/or protection states of an intelligent substation to accurately verify whether measuring and protection actions of the substation are accurate.