The invention discloses mesoporous carbon prepared by using a manganese compound, and a preparation method thereof. According to the method, manganese oxide crystal nanoparticles formed by decomposinga manganese compound during pyrolysis carbonization of a carbon precursor have mesoporous size characteristic, the manganese compound can catalyze the carbon precursor to form carbon, and the manganese compound is used as a template agent precursor so as to prepare mesoporous carbon. The method specifically comprises: 1, uniformly mixing a thermoplastic carbon precursor and a manganese compound through solid phase powder or a liquid phase solution; 2, carrying out high-temperature carbonizing on the mixture in an inert atmosphere to obtain a MnO-nanoparticle-coating carbide; and 3, uniformlymixing the carbide and a dilute acid solution, and removing MnO to obtain mesoporous carbon. According to the present invention, the prepared mesoporous carbon has characteristics of high specific surface area, high mesoporosity, large mesopore volume, easily-controlled pore structure and easily-controlled pore size distribution, can greatly reduce the carbonization temperature of the carbon precursor, and can be widely used in the fields of adsorption, catalysis and separation.