In order to analyze the drought resistance of sugarcane △1-pyrroline-5-carboxylate synthase gene (SoP5CS),SoP5CS was transformed into tobacco using Agrobacterium-mediated leaf discs method. Four transgenic tobacco lines with low copy numbers were screened for drought stress experiment. The results showed that both the relative expression levels of SoP5CS and its encoded protein were the lowest in T9 transgenic tobacco line under drought stress.Compared with T9,the relative expression level of SoP5CS in T1,T4 and T6 lines were 9.02-fold,3.93-fold and 8.51-fold while the protein level of SoP5CS in T1,T4 and T6 lines was 2.22-fold,3.91-fold and 1.36-fold,respectively.Results of further analyses showed that the contents of proline and ABA in the four transgenic lines were all significantly higher than those in the control.The contents of proline and ABA in T1 and T6 lines were higher than those in the other two lines. The MDA content in the control was significantly higher than that of the transgenic plants.The accumulation of MDA was the lowest in T1 line. The P5CR and P5CS activities were different between the control and transgenic plants.The activities of both enzymes in T1 and T4 lines were nearly the same as those in the control,significantly higher than those in T6 and T9 lines. The CAT activity was the highest in T6 line,which in the other transgenic lines significantly higher than that of the control. SOD activity in all the transgenic lines was significantly higher than that in the control,with which in T4 and T6 lines being relatively higher. The relative water content in the leaves of the transgenic lines was significantly higher than that in the control,while the chlorophyll reduction was lower. The result of RA comprehensive analysis showed that the drought resistance of T6 line was the best,followed by the T1 line,indicating that drought resistance of SoP5CS gene is strong.