We analyzed the mechanism of detecting the inter-turn short-circuit in rotor winding fault with detecting coil, and extracts the signal feature with wavelet transform algorithm. Hybrid programming of MATLAB and VC++ is used, embedding ding M document of MATLAB into the VC and making them run normally without MATLAB. The signal collecting, system frame constructing and interface drawing can be carried out by adopting VC++ graphical interface as the front-stage, while using COM builder technology to implement communication between MATLAB and VC++. With MATLAB as the back-stage, the inter-turn short-circuit in rotor windings fault can be judged through the data analysis and calculation. The results show that the system has a good effect in practical application.