The dominant asymptotic stress feild near the tip of a Mode-I crack of Yeoh-model-based rubber-like materials is determined. The analysis bases on the fully nonlinear equilibrium theory of incompressible hyperelastic solids. First, The nonlinear PDE (partial differential equation) governig the leading behavior of y2 is transformed to a linear PDE. Then the linear PDE is solved and the solution of y2 is obtained. With the solution of y2 and boundery conditions the numerical solution of y1 is obtained,too.Finally,the analysis solution in polar coordinate of the first Kirchhoff Stress in plane stress state is obtained .