We apply level set methods to create a new burning surface calculation algorithm, viewing burning surface as interface of different materials. New algorithm attains burning surface variation regulation of arbitrary configuration grain by tracing grain burning surface recession. In the full paper, we explain our new algorithm in detail, here we give onty a briefing. Our explanation centers around three topics: (1) calculation of burning surface area of complicated 3D grain; (2)calculation of burning surface area of grain with flaw; ^calculation of burning surface area of grain with changing burning rate. We used explicit weighted essentially nonoscillatory (WENO) discretization scheme and total variation diminishing (TVD) Runge-Kutta scheme in numerical simulation. Results show preliminarily tliat this new method has high calculation precision and good adaptability. This paper can be used to coupled grain burning surface recession process to the numerical simulation of SRM (solid rocket motor) chamber flowfield.