Combined with the advantages of low melting point,high thermal stability and strong acidity,a multipleSO_3H functioned ionic liquid(MIL) was developed successfully as a curing agent to promote the curing reaction of phthalonitrile-terminated poly(phthalazinone ether nitrile)(PPEN-Ph).The curing kinetics over differential scanning calorimetry(DSC) showed that both the initial curing temperature T_(p0’) and apparent activation energy Ea’(based on Kissinger equation) were reduced significantly over MIL(207.9℃ and 101.5 kJ/mol) compared to the common curing agent ZnCl_2(268.5℃ and 201.5 kJ/mol).Moreover,under identical curing conditions,the resulting thermosetting resin over former(T_(d5%)=526.1℃) showed better thermal stability than that over latter(T_(d5%)=512.1 ℃).These results indicated that MIL should be a good candidate as a curing agent for phthalonitrile resins. Combined with the advantages of low melting point, high thermal stability and strong acidity, a multiple SO_3H functioned ionic liquid (MIL) was developed successfully as a curing agent to promote the curing reaction of phthalonitrile-terminated poly (phthalazinone ether nitrile) (PPEN-Ph The curing kinetics over differential scanning calorimetry (DSC) showed that both of the initial curing temperature T_ (p0 ’) and the apparent activation energy Ea’ (based on Kissinger equation) were reduced significantly over MIL (207.9 ° C and 101.5 kJ / mol) Moreover, the resulting curingosetting resin over former (T_ (d5%) = 526.1 ° C) showed better thermal stability than that of latter (T_ (d5%) = 512.1 ° C.) These results indicated that MIL should be a good candidate as a curing agent for phthalonitrile resins.