Taking clustering ginger（Zingiber officinale Roscoe.）shoot as materials,we compared the doubling effects of its somatic cell chromosome under in vitro cultivation condition and with different colchicines concentration and different treating time period.The results showed that the inducement effect was the best,when shoots were treated in liquid culture medium of 0.2 % colchicines concentration for 8 days.The inducement and survival rate were 42.86 % and 70.00 %,respectively.The chromosome number of tetraploid was 2n=4x=44,while that of the control diploid was 2n=2x=22.Compared with diploid,tetraploid showed characteristics of taller plant height,thicker stem,larger,broader and thicker leaf blade,fewer stomata per unit area,larger stomata,and more chloroplasts in stomata guard cell.The stomata density and chloroplast number in guard cells could be important characteristics distinguishing tetraploid from diploid.