In order to further understand the effect of drought stress on the growth and physiological indexes of colored potato seedlings,and to determine the drought resistance ability of three new colored potato varieties Zicai 1,Zicai 2 and Zicai 3 were selected,and their male parent variety Heimeiren was used as the contrast in this study.The virus-free tissue culture seedlings of the tested potato varieties were treated with different concentrations of polyethylene glycol（PEG-6000） solution to simulate drought stress,and the physiological indexes such as plant apparent growth,root growth changes,Pro content,cell plasma membrane relative permeability and MDA content were observed and analyzed.The mean membership function method was used to evaluate the drought resistance of four potato varieties.The results showed that with the increase of PEG-6000 stress intensity,the effect of drought stress on the growth of plant and root of three new varieties was less than that of the control variety.The Pro content,cell membrane relative permeability and MDA content of the leaves of tissue cultured seedlings of each tested variety in-creased in different degrees with the increase of PEG-6000 stress intensity,while the increase range of Pro content was larger than that of Heimeiren,and the relative permeability of cytoplasmic membrane and the content of MDA of three new colored potato varieties were less than that of Heimeiren.According to the results of the comprehensive analysis of the average membership function,the order of drought resistance of each variety from strong to weak is Zicai 3 ＞ Zicai 2 ＞ Zicai 1 ＞ Heimeiren.