Abstract: Described in the essay are the actions as taken to improve the yield of the seamless steel tube.Addressing the problem of high cropping rate of the tube, relevant improvement proposal is worked out, i.e., optimizing the multiple range from the original double-length to triple-length.And a trial is made with some representative pipe sizes.The analysis reveals that given that pipe head/tail crop length remain the same, the cropping loss rate will be reduced by about 0.5%, and the yield increased by 0.5%owing to increasing the length of the pipe as rolled with each individual operation step, and changing the multiple length range of the light-wall pipe from the original double-length to the triple-length.As the multiple-length range is increased, the pipe blank length with the same size is increased, and thus with the same rolling cycle, the output is increased accordingly.Thanks to optimization of the multiple-length range, the annual operation cost will be cut down by at least 2 million RMB, while the output will be increased by 70 000 tons.