Taking Qujiang Gao Keng subinclined belt shaft head chamber as the engineering background, it's floor heave characteristics and mechanism and it's floor stress distribution were analyzed by theoretical analysis, numerical simulation, field test method. The main reason of floor heave and asymmetric deformation was frequent disturbed, unbalanced stress distribution and rock properties etc. To control the stability of surrounding rock of the chamber, the key measures is to control the uniform stress distribution, followed by controlling the shallow rock stress concentration degree, and finally improving the roadway surrounding rock. The surrounding rock deformation can be controlled. According to the principle of floor heave steps control,"the first step is to borehole pressure relief, the second step is to cable + channel + spray" is proposed and is put into effect in that tunnel. The new supporting scheme chamber plastic zone and stress change with original supporting scheme were compared by utilizing numerical simulation.Engineering practice shows that the new supporting scheme effect is good for controlling the relative displacement of head ends and the floor heave, the key measures is to control the uniform stress distribution