Abstract: Chondroitin sulfate (CS) is a negatively charged linear macromolecule polysaccharide interlaced with glucuronic acid and acetylgalactosamine. It has a variety of physiological activities, including repair of articular cartilage, antioxidant, lipid-lowering, anticoagulant, antithrombotic and antitumor, etc. However, the high molecular weight of CS restricts its effective use of many functions. Chondroitinase (Chase), as a type of lyase that degrades CS, can cleave CS to low-molecular-weight CS, which effectively overcomes the shortcomings of low bioavailability. Based on the author’s work, this article briefly introduces the biological activities of CS and low-molecular-weight CS, expounds on the catalytic mechanism of Chase cracking CS, systematically sorts out the types and sources of Chase, fermentation production and characterization, as well as research progress in recombinant expression and application, view intending to deeply understand the research status and development trend of low molecular weight CS and Chase, and promote the industrial production of Chase.