Abstract: The rheological property of debris flow is closely related to its dynamic characteristics and the study on rheological property is the focus in the geological disaster field. A series of tests on original paste samples, particle diameter smaller than 1 mm, of debris flow fan had been done with third generation Anton Paar rheometer Physica MCR301 and the influences of debris flow gravity, shearing rate, loading mode etc. on the rheological property of debris flow were studied. The study results show that the rheological curve of low gravity debris flow presents a logarithmic relationship and that high gravity debris flow presents exponential growth; under the same gravity and shearing rate, the relation of shearing stress and gravity is obtained; the shearing stress of debris flow is not related to the loading mode.