Abstarct: Lignin is one of the most aromatic biopolymers and forms a major part of the cell wall. Lignin has many roles in plant defense, lignin or lignin-like phenolic compounds often respond quickly to biotic and abiotic stresses. Soil salinity is one of the most important abiotic stress that has adverse effect on crop production and quality and is one of the limiting factors of rice and soybean cultivation worldwide. In this study, bioinformatics tools and microarray data were used to study lignin biosynthesis pathway genes. Some genes involved in lignin biosynthesis pathway are involved in plant resistance to salinity stress. Some lignin biosynthetic pathway genes such as PAL, 4CL, CCR were obtained in soybean (Dicotyledon) and rice (monocotyledon) plants. Coexperssion studies of these genes have been conducted to find coexxpression genes to the main genes and genes that have unknown function but are likely to be involved in lignin biosynthesis and other pathways. Evaluation of 4CL gene exxpression and its associate gene, Chalcone synthetase and STR gene as a coxpression with PAL and CCR gene in saline treated two sensitive (L17) and resistant (Williams) cultivars at two levels of 0, 200 mM and 4 time intervals 6, 24, and 48 hours, were performed by q-RT PCR. Gene exxpression results showed that the 4CL gene in Soybean sensitive cultivar had more exxpression than the resistant cultivar in the first 6 h and both cultivars had significant exxpression in 24 h. The exxpression of the CHs gene was similar to that of 4CL at 24 h and the STR gene increased at all times. Laboratory studies confirmed bioinformatics studies and showed that the Coexxpression genes had similar exxpression profiles. Promoter analysis showed that upstream of these genes there is a binding site for a number of transcxription factors involved in the biosynthesis of lignin and phenylpropanoids.