The invention discloses a sparse Bayesian-based fault locating method and system. The system comprises a preprocessing module, a data learning and training module, a prediction module, a data analysis module and a fault locating module, wherein the preprocessing module performs processing on input data and inputs the processed data to the prediction module and the data learning and training module for performing processing; the data learning and training module inputs the processed data to the prediction module; the prediction module transmits the processed data to the data analysis module for performing processing; the data analysis module inputs the processed data to the fault locating module; and the fault locating module inputs the processed data to a control center. According to the method and the system, data prediction is performed by adopting a sparse Bayesian learning method; the whole calculation process is sparsified; the functions of increasing the calculation speed and improving the prediction precision are achieved; and the influence of certain error data on a result can be eliminated.