Bonding agent is functional component to improve mechanical properties of solid propellant. A new bonding agent,3-allyl-5,5-dimethylhydantoin(ADMH) was synthesized by the Gabriel method. The condition of the reaction was n(DMH): n (allylbromine): n (methyl alcohol solvent of KOH)=1: 1: 1,and water was used as solvent. The yield of ADMH is 50% and its purity is 99.97%. Chemical structure of ADMH was identified by TG-DTA,UV,NMR,FT-IR and MS etc. Melting point of ADMH is 65-66 ℃ and its decomposition temperature is 168.3 ℃.