Hole Transport Layer (HTL) is an important factor affecting carrier transport balance in metal halide Perovskite Light-emitting Diodes (Pero-LEDs). Poly(3,4-ethylenedioxythiophene)∶Poly (styrene sulfonate) (PEDOT∶PSS) films are widely used as the HTL of Pero-LEDs due to their excellent conductive properties, light transmittance and simple solution preparation. However, the gap between the valence band of perovskite and the highest occupied molecular orbital (HOMO) energy level of PEDOT∶PSS film is large, which increases the hole injection barrier and thus reduces the device efficiency. Herein, a simple method of directly adding cesium chloride (CsCl) into PEDOT∶PSS aqueous solution improved the hole transport capacity of PEDOT∶PSS film significantly, making the carrier transport more balanced. Based on the modified PEDOT∶PSS film, the best device reaches high brightness of 124 012 cd/m2, and the maximum external quantum efficiency (EQE) reaches 1039%, respectively. Compared with the undoped samples, the maximum brightness increased by 2549%, and the maximum EQE increased by 63.88%.