The length of semiconducting single-walled carbon nanotubes(s-SWCNTs) is shortened during dispersion and separation. The existence of many ultra-short tubes with length less than 100nm will increase the lap resistance between tubes and increase the scattering probability of carriers, which will lead to the degradation of device performance. It is not beneficial to the development and application of high-performance carbon nanotube devices. However, there is still a lack of research on the separation of s-SWCNTs length in organic system, especially the controllable removal of ultra-short tubes. In this paper, a silica gel adsorption technology in organic system was developed, which successfully achieved the efficient removal of ultra-short carbon nanotubes and effectively regulated the length distribution of semiconducting carbon nanotubes. Prepared by the CNTs with length sorting, the on-state current and maximum transconductance of the transistors were 8.9μA/μm and 0.5mS/μm, which were about 300% and 250% respectively, higher than those of the device without length sorting.