Two kinds of ammonium-based ionic liquid, i.e. n-butylamine nitrate and dodecylamine acetate were synthesized. The effects of ammonium-based ionic liquid and crosslinking polyether demulsifier NJ-20 complexes on the dehydration of simulated crude oil emulsion were studied. When the dosage of 200mg·L-1 and the temperature of 50°C, two demulsifier complexes reached the dehydration rate of 75% and 91% in 2 hours, respectively.Then separate polyether demulsifier NJ-20 can only reach the dehydration rate of 65% at the same conditions. When the dosage of 200mg·L-1 and the temperature of 40°C, dodecylamine acetate complexing demulsifier reached the dehydration rate of 59% in 2 hours, which is much higher than that of polyether demulsifier NJ-20, displaying strong low temperature demulsification effect.