In order to evaluate the roundness error of large-scale sleeve, a roundness error measurement system of large-scale sleeve was established and its applied algorithms such as laser collimation, image processing and etc were investigated. First, the method that the system obtained roundness error of large-scale sleeve was introduced. Then, based on the measuring process, a filtering algorithm of minimum circumscribed circle which analyzed the point position forms was presented. Finally, filtering efficiency was analyzed. Computing time and the precision were compared with the similar algorithm. Experimental results indicate that the computing time of the filtering algorithm is shorter by more than 30% and the precision of the CCD measurement rod is 0.7 mm. The roundness error measurement system of large-scale sleeve can satisfy the requirement of the project and evaluate roundness error effectively.