Over the past decades, big successful developments have been achieved in Quantum Dots (QDs) materials with unique photonic and electronic properties. In the QDs family, lead Halide Perovskites (HPs) QDs are especially recognized for excellent Photoluminescence Quantum Yield (PLQY, 70%~100%), ambipolar carrier transport, wide color gamut (150% NTSC) and low-cost solution synthesis process, making them as promising materials for Light-Emitting Diodes (LEDs) toward high-performance lighting and displays. Compared to the organic-inorganic lead HPs (MAPbX₃ and FAPbX₃, X=Cl, Br and I), all-inorganic cesium-lead HPs (CsPbX₃) possess relatively higher stability and comparable optical properties, are more promising to fabricate devices for practical application. Since the first LEDs using CsPbBr₃ Quantum Dots (QDs) emitters, the PLQY and stability of QDs have been continually increasing. Despite the rapid improvement in terms of PLQY and stability, the mass synthesis of perovskites QDs has been seldom studied but very crucial for applications. In order to overcome the performance degradation of inorganic perovskite (CsPbBr₃) QDs during materials preparation with large quantities, a modified supersaturated recrystallization solution-process was proposed to prepare high-quality CsPbBr₃ QDs at room temperature. By adding hydrobromic acid (HBr) to accelerate the dissolution of the perovskite precursor, and introducing Lewis acid ligand to partially replace oleylamine (OAm), to realize the effective passivation of surface defect of CsPbBr₃ QDs. This method enables the synthesis of highly efficient luminescent CsPbBr₃ QDs with low cost and mass production. The experiment results show that the CsPbBr₃ QDs exhibit an emission peak at 517 nm with a narrow Full Width at Half Maximum (FWHM) of 17 nm. Meanwhile, the PLQY of the CsPbBr₃ QDs is measured to be as high as 95%. The X-Ray Diffraction (XRD) patterns of the CsPbBr₃ QDs show that its characteristic peaks located at 15.49°(100),21.85°(110),30.98°(200),38.17°(211),44.15°(220), which indicated the typical monoclinic structure of the CsPbBr₃ QDs (JCPDS No. 18-0364). The X-ray Photoelectron Spectroscopy (XPS) implied the CsPbBr₃QDs showed Br-rich composition, which the rich Br in CsPbBr₃QDs probably contributes to the excellent optical properties and good air-stability properties in the ambient environment. As a proof-of-concept device, a backlit White Light Emitting-Diode (WLED) was fabricated based on the CsPbBr₃ QDs. A mixture of the green CsPbBr₃ QDs and commercially available red phosphor functioned as the downconverters, and separated high-energy GaN blue light sources for photoexcitation, applied to emit white light. Consequently, the WLED device shows a luminous efficacy of 48.35 lm/W under an operating current of 20 mA. Meanwhile, the WLED exhibited a typical Electroluminescence (EL) spectra which contain three emission peaks, 454 nm peak of blue chip, 517 nm peak of green CsPbBr_3, and 620 nm peak of red phosphor, resperctively. Furthermore, we obtained the device with a CIE coordinate value of (0.30, 0.31) in CIE 1931 color space, which is quite close to the standard white color (0.33, 0.33). The WLED with high efficiency demonstrated the promising potential of CsPbBr₃QDs for domestic lighting, backlit display, and optical communication applications.