In this paper, a segment extraction-integrate algorithm based on polygon approximation and finite state machines for on-line Chinese characters recognition (OLCCR) is presented. With this method, the point with the smallest interior angle which is less than the given value is detected and the whole stroke is split into two adjacent curves by this point, which is called as a cut-off point or an inflexion. To each of the two curves, the same step is performed to detect the cut-off points respectively. The same operations are performed iteratively until the smallest interior angle in all the curves is larger than the given threshold value. All the cut-off points and the start-end points compose the stroke and every pair of adjacent points constructs a segment. After segments have been extracted, Finite State Machines is used to check whether the adjacent segments need combination thus redundant segments can be reduced. Experiments proved that this method has the advantages of less computing complexity and better approximating effect than other methods.