Modulating photoluminescent (PL) materials is crucial for applications such as super-resolution microscopy. The combination of PL materials and photoswitches can achieve this aim by utilizing isomerization of the photoswitches. Here we report an optically PL switchable system by mixing carbon quantum dots (CQDs) and diarylethene (DAE) molecular photoswitches. The PL on/off states of CQDs, switched with alternating visible and UV light, achieve a PL on/off ratio of ∼500 and stable reversibility over 20 cycles. The mechanism of our design is revealed by PL lifetime measurements, temperature-dependent PL spectroscopy, and density functional theory (DFT) calculations, confirming that efficient static quenching and the inner filter effect between CQDs and closed DAEs are the keys to achieving such outstanding performance.