Abstract: The optimization operation of isosurface is very common in the three-dimension reconstruction.In this paper,the author uses middle point choice to replace lineal insert-value and the method of making a strip of triangle to optimize the form and the storage structure of the triangle in the isosurface，thus improving drawing speed of three-dimension models greatly.

Key words: marching cubes, isosurface, middle point choice, strip making of triangle, three-dimension reconstruction