Abstract: This paper studied the support property of 2-leg shield powered support based on the plane frame mechanics model,defined the mechanics equilibrium region and the support ability on different roof-contacted varieties,and ana- lyzed some factors which influenced the support ability of powered support. Based on the studies above,combined with the support structure characteristics,the paper studied the reasonable position of prop cap in the canopy,gave the ana- lytical result of canopy aspect ratio,and provided the support load density estimation formula of powered support. The practices show that the results of the paper can well explain the support characteristics of 2-leg shield powered sup- port,and provide a guidance for the design of hydraulic powered support.