SARS-CoV-2 (COVID-19) complaint is a new strain of coronavirus (2019-nCoV) found in 2019 at Wuhan city, China. Till date, there is no specific treatment against Covid-19 infection. Computer-aided drug design (CADD) is one of the new approaches for identifying the lead compound in drug development. In the present study, we performed an in-silico study of the Triterpenoid compounds from Mangrove plant as potential COVID-19 main protease (Mpro) inhibitors, which are used as a potential medicine target. Mangroves are salt-tolerant plant, rich in secondary metabolites. Generally, more than 16% of triterpenes are present in the Mangrove plant and possess many Pharmacological activities. In this study we used Molecular Docking using Auto Dock software. The binding energies obtained from the docking of 6LU7 with Beta-amyrin, Betulin, germanicol, taraxerol, lupeol, lupane, simiarenol, Tirucallol, Ursolic acid, Oleanolic acid, and Alpha-amyrin were -8.37, -8.73, -8.06, -7.71, -8.32, -8.49, -8.16, -8.99, -9.24, -8.87 and -8.89 kcal/mol, respectively. Further, these results were also confirmed by drug-likeness properties by using Swiss ADME software. This study showed Triterpenoid compounds seemed to have the best potential to act as COVID-19 Mpro inhibitors and they have a potential lead compound for the development of drugs, which can be used against the SARS-CoV-2 virus. However, further research like in-vivo and in-vitro examines is necessary to investigate their potential medicinal use.