Liquid laser system has prominent predominance in restraining heat distortion and can achieve stable high-power laser output in long time. In liquid laser system, the gain distribution by ordinary two-sides-pumping has the characteristic of strong gain at the edge but weak at the center and it is very difficult to achieve single transverse mode output. A kind of multi-segments liquid laser system connected in series, with pumping mode between side-pumping and end-pumping is introduced, and the gain distribution and the transmission loss in the resonator are simulated. The simulated results show that the multi-segments liquid laser system connected in series can achieve approximate Gaussian gain distribution, the laser beam quality is very excellent, the transmission loss is little and the laser energy transmission efficiency is higher than 30%.