Solvent polishing engineering is adopted to remove the relatively loose defect layer without damaging carrier injection in blue perovskite light-emitting-diodes (PeLEDs). Synchronously, the polishing effects depending on the solvents are discussed in detail. Finally, optimized blue PeLEDs were obtained with a maximum external quantum efficiency of 5.18%, high brightness of 3737 cd m-2, and a low turn-on voltage of 3.2 V.