The low separation rate of electron-hole pairs in single-component photocatalysts severely limits their applications for wastewater treatment. For this study, SnO2/BiOCOOH photocatalysts in flower-like microspheres were controllably synthesized via a one-step hydrothermal method and were characterized by various advanced techniques. These SnO2/BiOCOOH nanocomposites demonstrated excellent photocatalytic activities for the degradation of rhodamine B (RhB), titan yellow, and levofloxacin hydrochloride (LVF). Specifically, 98.5% of RhB, 80% of titan yellow, and 85% of LVF were degraded under 5 W LED (λ = 365 nm) light irradiation within 30, 40, and 60 min, respectively. Radical trapping experiments and electron spin resonance results indicated that h+ was the dominant active radical, whereas ·O2- and ·OH played an auxiliary role in the photocatalytic system. Subsequently, a potential photocatalytic mechanism was proposed based on the experimental results.