AE signal is wide and high range in frequency. In this case we used generalized S transform to analysis AE signal in frequency domain and choose the parameter made the generalized S transform has a frequency resolution ranged 1khz~2khz in the frequency ranged 20khz~1000khz .and then we filter the AE signal and extract it’s characteristics based on the generalized S transform . and at last we diagnosis the condition of Mechanical seal by the method of GA-TWSVM and get a 100% accuracy rate which is high than the accuracy rate of GA-SVM. the result shows TWSVM is better than SVM in pattern recognition.