The invention discloses a straight line detection and screening method under a complex environment. A straight line detection algorithm based on segment fusion is adopted, so the accuracy of the straight line detection is greatly improved, and a boundary straight line can be accurately extracted; a straight line detection algorithm based on a Gaussian model is adopted, and all detected straight lines are screened, so that a target straight line is retained and irrelevant straight lines are rejected. Moreover, even if the target straight line is partially blocked or has a problem of local overexposure, the target straight line can still be detected and screened out, and the practical value is fully realized. The straight line finally obtained can be used in the tasks of robot location, line walking and the like.