The electroluminescence efficiency of perovskite light-emitting diodes (PeLEDs) has gained notable achievements, but the poor stability under electric stress severely impedes future practical use. Here, an alkyldiammonium 1,4-butanediamine (BDA) is incorporated into perovskite emitting layer, which substantially optimizes electrochemical stability and minimizes interfacial deep traps under large external bias. The BDA-PeLED shows a record operational half-lifetime T of 189.4 h at a high current density of 100 mA cm and 681 h under 50 mA cm. Additionally, the device maintains its original performance upon 2500 cycles of voltage scan and withstands 10 000 times of ON–OFF under a pulsed voltage of 2.5 V. Further degradation mechanism study reveals that the main origins of the instability property of PeLEDs without BDA are the generation of deep traps at the interfaces and the infiltration of anions into adjacent layers under long-term electric stress. The significantly enhanced electrochemical stability suggests that alkyldiammonium cation incorporation can provide a direction to solve the instability issue of PeLEDs.