Feature extraction and evaluation is the basis of detection and prognosis. Aiming at tooth breakage in 2K-H planetary gear sets, damage model of planetary gear sets was developed. After the analysis of simulation signals, features based on sidebands around dominant frequency, wavelet transform and EMD were presented and valuated with two samples consistency check. Then the features extracted in the above were verified by simulation signal and test data. Validation results show that the features are promising and the feature based on sideband around dominant frequency is the best one to detect damage for 2K-H planetary gear sets.