The tunnel construction is also one of the key projects of highway engineering construction. Compared with other road sections, tunnel environment construction is more complicated due to the semi-closed environment of tunnel engineering itself, and the vehicle operation accident rate of the overall section of tunnel is relatively high. In addition, due to the poor air circulation in the tunnel environment, it is easy to cause traffic congestion or serious traffic hazards during the operation of vehicles. This paper firstly elaborates and analyses the characteristics of road tunnel fires, and on this basis, summarizes the safety hazards that can easily trigger fire problems in road tunnels, and at the end of the paper, summarizes the optimal design of fire extinguishing systems in road tunnels, aiming to provide experience for technical personnel of the future project to study the design of fire extinguishing systems.