In this paper, we propose a matching algorithm for radical-based on-line Chinese character recognition. The major effort of this paper is to demonstrate recognition procedures for subcharacters, such as radicals and residual subcharacters, and nonradical characters. Since a Chinese character could have front radical, rear radical or none of them, the matching algorithm should be able to take care of all these conditions. Furthermore, instead of picking up the front/rear radical strokes from the input character before the matching process is taken, our matching algorithm determines how many strokes the front/rear radical should be during the matching process; it thus enjoys the property of flexibility. After the radical type and the number of strokes of the radical are figured out, the residual subcharacter can be picked up and submitted for matching again. By sequentially recognizing the types of front/rear radicals and the types of residual subcharacters, we can determine what the input characters are.