Inorganic CsPbIBr₂ perovskite features high phase stability and light absorption coefficient, making it suitable for the development of perovskite tandem cells or semi-transparent cells. High-quality CsPbIBr₂ perovskite films are of crucial importance for fabricating efficient solar cells. However, compared with CsPbI₂ and CsPbI₂Br, the CsPbIBr₂ precursor has poor crystallinity and low film coverage, which is prone to generating pinholes and defects. Therefore, serious charge recombination often occurs inside the devices. To solve this problem, p-aminobenzoic acid (PABA) is added to the CsPbIBr₂ precursor to regulate its crystallization dynamics in this work. Electrostatic potential distribution of PABA shows that the electron-rich regions (negative charge regions) are mainly located near the C=O. Fourier transform infrared spectrum indicates the existence of coordination interaction between C=O and Pb²⁺ and the formation of hydrogen bonds between —NH₂ and halide anions. Ultraviolet-visible absorption (UV-Vis) spectrum and X-ray diffraction (XRD) spectrum demonstrate that a new intermediate phase, PABA·Pb···Br(I), is formed between PABA molecules and the components of CsPbIBr₂ precursor. The formation of this intermediate phase slows down the crystallization rate of the perovskite, regulates the grain growth, and enables the preparation of dense perovskite films. XRD, UV-Vis, space charge limited current, and linear sweep voltammetry are used to characterize the film quality. After the addition of PABA, the film quality of CsPbIBr₂ perovskite is improved. Thus, the light absorption is enhanced. The defect density is reduced. And the conductivity is increased. The efficiency of the champion cell increases to 10.65% compared with that of the control cell (8.76%). Further, dark current-voltage curves, Mott-Schottky curves, electrochemical impedance spectra, and photoluminescence spectra are utilized to analyze the reasons for the improved photovoltaic performance. After the addition of PABA, the CsPbIBr₂ device exhibits reduced leakage current, enhanced built-in electric field, suppressed charge recombination, and improved charge extraction at the interface. In addition to the enhancement in photovoltaic efficiency, the PABA-regulated perovskite cells also exhibit high stability. After being stored in air for 1500 h, the average efficiency of the unencapsulated cells remains 80% of the initial value.