Abstract: In vertical polyacrylamide slab gel electrophoresis analysis,the band patterns of esterase isozymes obtained from resistance differing sweet potato varieties to Pseudomonas solanaccarum are composed of many enzyme bands in proper ratio.The high,medium or susceptoble resistance varieties had their own band patters of esterase isozynes.Pattern 6 represents high resistance,pattern 4 medium and pattern 5,7,10 susceptible.The band patterns of esterase isozymes can be used as one of biochemical criteria in identification of the variety resistance,Being analyzed by ultraiolet ray screening,the ratio of OD readings in Pa area of peroxidase isozymes in diseased or health seedlings of sweet potato can also be used as one of biochemical criteria in identification of the variety resistance.