A upper estimate function v(x) of Hausdorff measure H’(S) of Sierpinski Gas-ket is given. A mathematical representation of the upper approximate value uN(x)to u(x) and a simple algorithm of uN(x) based on lattice tracing technique are also derived. As a simple corollary, the estimation H’(S) min u15(n 10-5)=u15(0.50783)=0.81794’is obtained.