Perovskite quantum dot (QD)light-emitting diodes are novel generation display technique with great potential.All-inorganic CsPbX₃ (X=Cl,Br,I)QDs exhibit excellent optoelectronic properties. However, the synthesis of CsPbX₃ QDs usually requires the long-chain ligands such as oleic acid (OA) and oleylamine (OAm). The dynamic binding between these ligands and QDs makes them easily detach from the QD surface, thereby leading to the poor stability. In addition, the insulating properties of OA and OAm are not conducive to the charge transfer. In this work, we adopt the strategy of replacing OA with 2-hexyldecanoic acid (DA) partially, systematically studying the influence of DA/OA molar ratios on the optical properties of CsPbBr₃ QDs. The results show that CsPbBr₃ QDs modified by DA exhibit a high photoluminescence quantum yield of 88.64%. Based on this strategy, the all-solution-processed light-emitting diodes achieve the luminance of 155 cd·m^-2 and external quantum efficiency (EQE) of 0.14%. Subsequently, by optimizing the energy levels between the perovskite layer and the hole transport layer, the luminance and EQE are further improved to 436 cd·m^-2 and 0.20%.