The invention provides a non-contact measurement method for sizes of forged pieces. According to the non-contact measurement method, feature points are scanned and acquired through cooperation of a linear array CCD and linear structured light, three-dimensional coordinates of the feature points are deduced and three-dimensional modeling are performed on the basis of the optical triangle principle, and thus information such as sizes of the forged pieces is obtained through analysis. Through the measurement device and method, the system resolution is improved, the system measurement range is widened, the problem of target matching in binocular vision is avoided, and large-size three-dimensional high-precision measurement can be achieved.