Abstarct: Caloropis procera is one of the valuable medicinal plants of the family Asclepiadaceae, whose success or failure of establishment is strongly influenced by salinity. In general, soil salinity has a significant effect on the growth and development of plants and induces a variety of defense responses, such as gene exxpression regulation and mextabolic processes.In this study; bioinformatics tools were used to study flavonoid biosynthesis pathway genes. Some genes involved in flavonoid biosynthesis pathway are involved in plant resistance to salinity stress. Some flavonoid biosynthetic pathway genes such as PAL;4CL;CCR;CHS & ND1 were obtained in Arabidopsis (Dycotyledon); as a family member of the calotropis procera plant and rice (Monocotyledon) plants.Coxperssion studies of these gene have been conducted to find coxpression genes to the main genes and genes that have unknown function and other pathway.The present study was designed to investigate the exxpression levels of some of the genes involved in the biosynthetic pathway of flavonoids such as CHS and Nd1 at two salinity levels.The study was conducted in a completely randomized design with three replications at two different salinity levels (0 and 100 mM NaCl) and 4 time intervals (6, 24, 48 and 72 h). Laboratory studies confirmed bioinformatics studies and showed that the coxpression genes and similar xpression profiles. The results of this study showed that the exxpression of CHS and Nd1 genes under salinity significantly increased under stress conditions. The results also showed that the exxpression of CHS and Nd1 increased and decreased again with increasing stress duration. Results showed that exxpression of CHS and Nd1 genes increased significantly in the first 24 hours after salinity stress. The exxpression of the CHS gene increased about 9-fold over the 24-hour period compared to the control, a 5-fold increase in the Nd1 gene compared to the control. Due to the increasing and then decreasing trend as well as free radicals neutralization by flavonoids, it can be concluded that the CHS and Nd1 genes play an important role in the primordial response to salinity stress and further studies on their exact role under salinity stress should be carried out.