Chemical oxygen-iodine laser (COIL) is unique chemical laser based on electronic transition of iodine atom with wavelength 1 .3 1 5 tm. Measurement of gas-dynamic parameters of the active medium by pneumometric methods looks like the basic at present. Accuracy of these methods is not always high enough. Laser spectrometry methods give an additional opportunity of active medium parameters measurement. Distant methods allow making measurements without penetration inside the laser active medium. Additionally, several parameters like pressure, temperature and velocity can be detected simultaneously with small response time and high accuracy. The data processing algorithm for such measurements is presented.