Jaw crusher is a kind of machine widely used in mining and aggregates industry, but it still has some shortcomings, such as liners wear, terrible power draw etc. The lack of research on material flow strongly limits the design improvement. The size reduction of the jaw crusher relies on the moving jaw movement that is a kind of complicated swing. Based on the movement analysis of the moving jaw and the single particle breakage characters, the material flow is analyzed. The measure of the breakage force is carried out. Material flow analysis is partly confirmed by the experimental results and some new information is also learned from the crushing force distribution. The job on the material flow will be helpful to the jaw crusher design improvement.