Herein, we report an ammonia-responsive of lanthanide (Eu(Sal)3, Sal = salicylic acid) complexes hydrogel sensors based on the amine molecule affecting the energy transfer process. In this system, the ammonia stimulation causes the coordination and decomposition of Eu(Sal)3 in the hydrogel, thus leading the fluorescence quenching and recovery of Sal in the ammonia atmosphere. Furthermore, the EuLn-Fm/PVA hydrogel composed of Eu(Sal)3 and Eu(TTA)3 complexes (TTA = 2-Thenoyltrifluoroacetone, L = Sal and TTA, Fm = formamide, n = 1-3) was prepared by an one-pot process, which achieves the continuous detection for ammonia gas. Meanwhile, EuLn-Fm/PVA hydrogel also achieved diverse responses for ammonia gas. This device could be a promising strategy for developing fluorescence hydrogels with potential applications due to its desirable advantages such as simple preparation, cost-effectiveness, etc..