The partieles' motion o sereen surface was studied by the way of nonliesr dynamics. It was found that the particles'motion may be changed form one form to another with its vibration strength. When the vibration strength K is bigger than 1 and smaller than 1.33, the partiele' motion is the bifurcating typet; when K is biger than 1.33 and smaller than 1.67, its motion becomes the double bifureation type; when K is bigger thaan 1.67, its motion changes into chaos motion type. On basis of studying alll effects of large vibration strength on particles penetrating, its was pointed out that a larger vibration strength K of screen surface will increase the strength of particles' motion. and then increase their probability of penetrating screen surface. A primary theory of particles' motion under large vibration strength for moisture fine coal was established.