The genic variation analysis of Pseudomonas aeruginosa after filtering the spurious variation appeared that 222 variable loci out of 5572 loci were detected. The type of variation analysis revealed that single nucleotide polymorphism was highly significant compared with other types of variation due the fact that the genome variation was achieved on the level of microevolution. Moreover, the proportional effect of functional scheme showed that genes responsible for environmental information were the highest comparable to another scheme. The genes of environmental information processing locate on outer membrane and face the defense strategy of the host therefore change in proteins coded by these genes lead to escape the immune system defense strategies. Furthermore, the non-synonymous change was the highest comparable with synonymous change among environmental information processing genes. Another significant result was represented by the fact that variation was located in the conserved domain for the proteins coded by genes responsible for environmental information in 29 out 0f 31. One of the factors that lead to adapt isolates with the bad environmental conditions is the location of the variation for proteins within conserved domain. Phylogenetic analysis indicates that significant level for variation correlated with environmental information processing genes comparable with other schemes