Abstract: The position for stratification plane gliding and its function play a key role in mining subsidence calculation. Based on the theory of composite plate, this paper derived a 3 D function of stratification plane gliding and a 3 D formula for the position of stratification plane gliding in mining subsidence, and obtained a formula for maximum gliding direction on the gliding plane. The applicability of the formulae is proved through the observation data from a model made of materials similar to those in field.