Abstract: The paper investigates the chatter phenomenon about 120~250Hz often occurred during the rolling of cold strips establishes a more reasonable dynamic model of the chatter, and simulates the chatter process. The chatter is a self-excited vibration resulting from the inherent instability of rolling process increasing with rising rolling speed. The limit speed up to which the chatter occurs varies with difference of technology parameters of rolling and specification of cold mill. The mistakes about chatter mechanism existing in the research articles of some foreign investigators are pointed. The measurements which may prevent from chattering with reasonable design and operation of cold mill are given by the analysis and simulation.