A new synthetic route for preparation of 1,3-diamino-5-methylamino-2,4,6-trinitrobenzene with chlorobenzene as the starting material was reported. Via the sequence nitration-nucleophilic substitution-vicarious nucleophilic substitution of hydrogen reaction, the title product was obtained with yield of 60.3%. The structure of the title product and its intermediate products were identified by IR, ¹H NMR, and elemental analysis. DSC curve of the title product shows the peak temperature of thermal decomposition is 303 ℃, which indicates its molecule is stable to heat.