Abstract: Based on the engineering tests on relative deformation of the lateral tunnel rock and the top and bottom tunnel rock,the variation of tunnel rock deformation with time during different periods was analyzed,and the attenuating coefficients of the first creep deformation and the secondary creep deformation were obtained.The tunnel rock stability was deduced through measuring shelf support force.Combined with the attenuating coefficient of the first creep deformation and the secondary creep deformation and the shelf support force,a method of engineering evaluation of allowable deformation of soft rock was deduced,and it could be used to optimize the support parameters.