Quasi-continuous signal is an important form of modulation signal, which is widely used in many fields. Quasi-continuous modulation laser absorption spectroscopy was one of the typical applications of quasi-continuous signal, includes advantageous features of speediness, sensitivity and accuracy. In the environment of earthquakes, landslides, fires and other disasters, it was possible to produce CO, which was a kind of extremely flammable, explosive, toxic and harmful gas, due to the accumulation of complex closed environment and incomplete combustion. Therefore, to avoid the second explosion injury, rescue robot need to monitor and analyze the gas environment in the disaster scene. CO was the research object in this system. An experimental system for quasi-continuous modulation laser absorption spectroscopy measurement was established. The system has carried out CO measurement experiments by changing concentration, pressure and temperature, achieved the formulas for the relationship between second harmonic signal and CO concentration, pressure and temperature in actual CO measurements respectively. These formulas can be used to automatically compensate CO concentration according to the real-time pressure and temperature value during the rescue robot′s measurement in the disaster scene.(2012YQ06016501); 天津中德应用技术大学科技培育重点项目(zdkt2016-001)