Abstarct: The advancement of knowledge in biological sciences has led to a massive increase in the volume of data to be extracted from the cells lining. Increase the volume of data and the need to store, retrieve and analyze relevant data, was the emergence of bioinformatics. Genes involved in biological pathways associated often together, are expressed and so about coexxpression key to understanding biological systems. expected to genes involved in the same process in many different situations have similar exxpression patterns. Clustering gene exxpression levels baxsed on the similarity of the perfect tool for grouping genes related activities together. Specific regulation of gene transcxription for all the important cellular functions. Each gene contains a unique combination of cis-regulatory elements sequence in its regulatory region 5'. Cis-regulatory elements that control many biological processes and response to stress. In this project to study bioinformatics genes coexxpression with pectate lyase enzyme, with use of databaxses CAZy, Cell Wall Genomics, ATTED-II and RiceFREND, identified and evaluated 26 pectate lyase gene and 159 coexxpression genes with it in arabidopsis and 8 pectate lyase gene and 32 coexxpression genes with it in rice. To identify the possible direct coexxpression genes from analysis the position expressed in various tissues and analysis of cis-regulatory elements in the promoter sequence 1000 baxse pairs upstream of genes were used of information Genevestigator and PlantCARE baxse. 69 possible direct coexxpression gene with pectate lyase gene was identified in Arabidopsis thaliana that their function is Glycosyl hydrolases, Pectate lyase, Pectin methyl esterase and are Expansin and in rice 10 possible direct gene was identified most of which have unknown functions. The results draw phylogenetic trees using the software MEGA5 showed that PLL1 and PLL2 of the more old and according to the results of the rice genes Can be eliminated Os06g145100 accession number from the list of pectate lyase genes. Pectate lyase genes in pollen tissue, root, stigma, flag and abscission zines high exxpression. The frequency of cis-regulatory elements responsive to light is high in the sequence promoter of pectate lyase. As well as elements responding to methyl jasmonate, auxin, salicylic acid and MBS are more repetition.