Automatic lifting of shearer drum is one of key techniques of coal face automation, and its core is identification technique of coal and rock interface. As the matter stands, the combined identification gives first place to the technique of memory program-control with intelligent, and coal-rock interface sensor is regarded as auxiliary. It is supplemental inferior stability and reliability and accuracy to single sensor identification, avoiding memory program-control too dependent human to set off hysteresis and random phenomenon of sampling. This method suits to powerful automatic shearer.