Among four natural populations of Drosophila melanogaster, the genotype distribution and specific enzyme activity of amylase(Amy) were analysed from total 588 isofemale lines from 1996 to 1997. Total patterns of Amy variants have been found as Amy¹,¹·²,¹·³,¹·⁴,^(1·5),^(4·5), and ¹·²·³. At these genotypes it revealed that Amy¹ seems to be the commonest and an ancestral allele and that all population has to be like the distribution. The protein concentration and enzyme activity of amylase variants were detected by Lowry assay and starch-iodine assay. The average of protein content was shown similarly as 13.1226 ㎍ Protein. Specific amylase activity of the Amy¹was used standard enzyme activity. Each enzyme activities in adult single fly of Amy variants were revealed as similar as 1.9695 ㎍ Maltose/㎍ Protein of Crude extract/min. Also, of competetion among Amy variants were analysed the distribution and the frequency after cage flies were underwent the competetion of the survival. We have the same result as that of natural population. Amy¹ and Amy¹·³ were the commonest.