This paper introduces a new method, called the projection filling, to fill any regions based on contour structure points. Four types of the structure points are detected based on the structure pattern models of chain codes of contours. The projection filling proceeds between each pair of the neighbouring structural points (filling section) parallelly. The new filling algorithm can fill any regions including some contours which can not be filled by traditional filling algorithms, such as the "seed" and the "even-odd" algorithms. The projection filling method can be used in image analysis, recognition and computer graphics.