2,3,5,6-tetraaminopyrazine (TAPA) was synthesized from iminodiacetonitrile through nitrosation, cyclization, nitration and reduction. The structure of the target product as well as that of the intermediates of each reaction was confirmed by NMR, IR, ESI-MS. The overall yield was 26.8%. The effects of different cyclization reaction temperatures and nitration systems on the yields of intermediates were investigated respectively. In addition, the influence factors of hydrogenation reduction reaction were discussed. The optimal conditions were determined as follows: The temperature of cyclization reaction was 25℃;In the nitration reaction, the best system of nitration was selected as KNO3 and fuming H2SO4; In the reduction reaction, the mass ratio of Pd/C to 2,6-diamino-3,5-dinitropyrazine-1-oxide was 1:15, the best solvent system was selected as CH3OH and H2O (volume ratio 1:1), the reaction temperature was 55℃ and hydrogen pressure was in 0.8～1.2MPa . The advantages of this new synthetic route were that the starting material was commercially available and that the intermediates had good stability, which can reduce the cost of synthesis greatly.