Based on the statistical data of cable tunnel fire accidents at home and abroad in recent years, the causes and characteristics of cable tunnel fire accidents are summarized and the various fire extinguishing systems are introduced, such as water spray fire extinguishing system, high-pressure water mist fire extinguishing system, gas fire extinguishing system, aerosol fire extinguishing system and ultra-fine dry powder extinguishing system. According to the analysis of technology and economics, it is recommended to adopt the high-pressure water mist fire extinguishing system in the longdistance and largevolume cable tunnels, and the ultrafine dry powder fire extinguishing system is recommended in the cable joints or other key protection areas for local fire extinguishing. However, it is not recommended to use gas fire extinguishing system, water spray fire extinguishing system and aerosol fire extinguishing system in longdistance and large-volume cable tunnels.