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This paper analyzed the smashing theory of straight blades, crescent blades and bent blades respectively. With the velocity of roller, the machine speed and the depth in the dust as the test factors, and the percent of pass and the power consumption as the test indexes, the experiments were carried out subsequently. The advantages of crescent blades, such as small disturbance, low power consumption and high pass percent were validated by experiment. Finally, the regressive mathematic model of crescent blades smashing performance was established and the optimum parameters were obtained by regressive analysis.  