Objectives: There are so many in-vitro and in-vivo studies proved the hepatoprotective and antiviral effect of silymarin and derivatives. Number of antiviral activities of Silymarin and derivatives has shown against liver and non-liver pathogens, it indicates potential broad spectrum antiviral. In addition, considering the poly-pharmacological activity of silymarin and derivatives towards multiple host cell targets, such as cell innate immunity and inflammation, oxidative stress production, and autophagy, which are all cell physiological processes that are known to be elicited or subverted by many viral infections, these natural products are likely to exert their antiviral activities by modulating the cellular environment in addition to any potential direct antiviral function(s) against a specific viral protein. Highly contagious SARS-CoV-2 causes high grade fever with joint pain and lethal organ injuries. The infection of COVID-19 across world has led to a global health emergency. COVID-19 disease caused by the severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) has affected nearly all the continents with around 1.52 million confirmed cases worldwide. Methods: In the present research an attempt had been made to find new COVID-19 main protease inhibitor by molecular docking approach. Grid based docking approach has been selected to find out the binding using AutoDock software. The two-dimensional structure of was converted into 3-D structure and optimized with 3D geometry. Results: Silibinin, are extracts obtained from the medicinal plant milk thistle (Silybum marianum) and have conventionally been used for the treatment of liver diseases. It is major constituent of Silymarin. Recent studies reported its significant in anti-neoplastic effects in a diversity of in vitro and in vivo cancer models, including skin, breast, lung, colon, bladder, prostate and kidney carcinomas. The Silibinin was docked and the binding energy was found to be -7.92 kcal/mol. .....