Abstract: In order to simulate the dynamic burning process in a pasture,the burning trajectory model of the Polygon-Curve is created,which composed of arcs in point visible polygon and of line segments in line visible polygon.Firstly,the point visible and the direction visible techniques are used to complete the deep visible division of a simple polygon.Then,in each divided sub-polygon,the mini-max distances of each vector edge to its viewpoint or view line are calculated,which can be used to achieve the calculation of mini-max shortest paths between the initial burning line to any edge or to any visible sub-polygon.Finally,Total 17 kinds of locations for the position relationships of a circle to vector lines and 9 kinds of locations for the position relationships of a line to vector lines are calculated.By used of these position relationships,the into-point and out-point are found and the arcs or line segments of burning trajectory are draw,and the algorithm is programmed by VC+ + and several testing examples are examined.Experimental results show that this algorithm can achieve such things that drawing the burning trajectories at different times,computing the burning times in different positions,estimating the longest distance and the longest time of burning etc.