A borate ester bonding agent with a five-membered ring was synthesized via a "one-pot" process using borate acid, ethylene glycol and 1, 2, 4-butanetriol as raw materials. Its structure was characterized by FTIR, ¹¹B NMR, ¹H NMR and MS. The hydrolysis reaction kinetics of the synthesized borate ester in normal temperature water and in saturated water vapor was investigated by an on-line IR analysis method. The hydrolysis reaction kinetic model was established. The results show that the hydrolysis of the synthesized borate ester under above-mentioned two conditions is the pseudo-first order reaction. The reaction rate constant and half life of the borate ester are 2.3×10^-5 s^-1 and 8.4 h in normal temperature water, 2.96×10^-7 s^-1 and 27 d in saturated water vapor, respectively. The addition of 0.2% borate ester makes the tensile strength of RDX/HTPB explosive increase from 0.80 MPa to 1.44 MPa and the compressive strength increase from 5.04 MPa to 13.27 MPa, proving that the synthesized borate ester has good bonding effect.