This paper concerns mine hoist braking system fault diagnosis with the combination of wavelet packet and support vector machine. It is motivated by the scarce of fault samples in mine hoist such requiring very high security system. A novel approach is presented in order to diagnose blockage piston in cylinder, a typical fault of mine hoist braking system. This method mainly consists of three steps: (1) apply 3 levels wavelet package to construct and reconstruct signal of brake distance-time , extract fault feature vectors (2) set up training samples (3) establish a SVM fault classifier to complete fault diagnosis. Experimental results show that SVM method can effectively accomplish the blockage piston in cylinder fault diagnosis of braking system and has a high adaptability for fault diagnosis in the case of smaller number of samples.