A new method for line detection based on chain code detection is proposed. First of all, chain codes are tracked in an edge image. After the curvature estimated, the corners in chain codes can be detected, and chain codes are separated at the corners. Chain codes of line segments are recognized, and only the chain codes, which represent line segments, are kept. Parameters of line segments are estimated according to the chain codes, and the piecewise line segments are linked based on the linking criterions. Experiments with images show that the method is effective for line detection.