A fault diagnosis algorithm based on relative transformation independent component analysis(ICA) of multiblock(MBRTICA) is proposed to solve the problems caused by unsatisfactory data separability, noise interference and difficulties in tracing faults during the industrial complicated processes. In order to improve the separability of extracted fault features, relative transformation ICA method is used to detect the occurrence of faults by combining the relative transformation principle and FastICA algorithm. By introducing the multi-block theory, the high-dimensional data is divided into multiple sub-blocks, and the RTICA algorithm is performed in each sub-block unit to determine the location of the fault. The proposed algorithm is validated by the spindle experiment with bearing crack fault. The experimental results show that, the fault diagnosis algorithm based on MBRTICA can improve the separability of data and effectively reduce the noise, which can improve the fault detection precision, and realize the fault location function to carry out comprehensive fault analysis.