The defect state and energy level matching in CsPbBr3 perovskite solar cells (PSCs) are the main factors affecting the photoelectric conversion efficiency (PCE). In this  work, we report a synergic post-treatment strategy based on SnBr4 to simultaneously  modulate the defect state and energy level arrangement, which can effectively suppress the  charge recombination loss and reduce the barrier of interfacial charge extraction. Consequently, the carrier transport properties of the CsPbBr3 PSCs are significantly  improved. The all-inorganic CsPbBr3 carbon-based PSCs without a hole transport layer  optimized with SnBr4 have achieved a champion efficiency of 8.29%, which increases larger by 33% in average.