Abstract: Polygon convex decomposition is one of the fundamental problems in computational geometry. It is used in many fields. Most of the algorithms now available are global searching ones. Local searching algorithms are rarely studied. The global searching algorithms waste so much time that they cannot meet the need of all the engineering problems. Presently the most classical local searching method is Rogers algorithm. But as it has many limitations, it is restricted in some actual use. In this paper, a new local searching algorithm is proposed based on the polygon point visibility. The local geometrical property is fully used in the algorithm. The cutting\|line is obtained from the concave point to the visible point which is carefully searched from the visible point list of this concave point by using weight function. Alternatively, the cutting\|line is found from concave point to the intersection point which is located on the visible point line and the bisector of the concave angle associated with the concave point. The presented algorithm has been applied in the plant design system of PDSOFT Piping, and the results obtained are remarkable.