A metal (Co)-Organic Framework (Co-MOF) was first found to catalyze the chemiluminescence (CL) of luminol. On the basis of X-ray photoelectron spectroscopy, powder X-ray diffraction, CL spectral, UV-visible absorption spectral, and electron spin resonance (ESR) spectral studies, as well as the research of the influence of various free radical scavengers, a possible CL mechanism was proposed. The enhanced CL might be attributed to the formation of a peroxide analogous complex between the oxygen-related radicals and the active metal site of the Co-MOF material. The established Co-MOF-luminol CL system was successfully applied to determine L-cysteine (CySH), based on the selective and sensitive enhancing effect of CySH on this CL system. Under the optimized conditions, CySH was selectively detected in the range 0.1-10 μM with a detection limit of 18 nM. This novel CL system obviously gives impetus to the new research field of metal-organic frameworks (MOFs) in chemiluminescence.