Abstract: To obtain the features of acoustic emission signals and their variation laws under the condition of hydraulic turbine cavitation, a series of cavitation experiments were conducted for a Francis turbine model, during which the acoustic emission signals were collected at typical measuring points under different cavitation conditions, while following features were extracted in a conventional analysis way, such as the event count, hit count, frequency center and the root mean square value of voltages, etc., so as to analyze the effects of cavitation coefficient on above features. Results show that with the decrease of turbine cavitation coefficient, the cavitation state changes from none to incipient, and further to fully-developed status; correspondingly, the features of acoustic emission signals vary in an obvious regularity; as a whole, the event count decreases gradually, while other three features increase, and their variation amplitudes depend on the stage in a cavitation process.