Intennittent flow, a common patterm of movement of víscous debris flows occurring in nature, is viewed as a wave phenomenon in the paper. According to plenty of field investigation and experiment infonnation, the first part of this paper discussed in detail temporal and spatial characteristics of wave shape, velocity, period, etc. The
wave decomposítion, overlap and movement way are also described deeply. Then
some new conclusions are obtained:
1) the wave front moves forward in a scrol1ing way on the bed with thin slurry of debris flows;
2) the velocity profile of body of debris flows is divided into three sections: gent1e flow, steep flow and plug flow;
3) the intennittent flow is super-critical flow that only propagates towards downstream;
4) the wave is proved to be non-periodic by the periodic analysis of intermittent time;
5) the wave movement is classified into three types: ground swell, short roll wave, long roll wave.
In the second part the movement is reduced to a kínd of shallow flow wave because it has three features: gravity driving, free surface, the ratio of flow depth and wavelength less than 0.4. After that MAC(marker and cell) method

is applied to solve a generalized two-dimensional problem of debris flows and the upwind scheme is adopted in order to reflect hyperbolic characteristic of the equation. The results of computation indicate:
1) the intennittent wave can appear spontaneously even if the upstream discharge is contmuous;
2) As time lapses the wave is unstable under some certain conditíons such as
large slope or zero roughness;
3) ifthe slope is equal to zero the íntennittent wave would not occur.
So the wave movement is relevant to slope and roughness, and there are some intrinsic mechanisms behind the phenomena. We think the mechanisms lie in nonlinear shal10w wave equation and non-Newtonian fluid model.