In order to avoid the serious energy w astage and unnecessary interference using xenon arc lamps as the broadband hot l ight source in active differential optical absorption spectroscope (DOAS) system s,the light emitting diode (LED) is developed as a new type of cold light source for optical remote sensing DOAS systems in this paper.A study on calibrating an d inversing method of light emitting diodes differential optical absorption spec troscopy (LEDs-DOAS) system is introduced.Firstly,the structure of LEDs-DOAS s ystem is described,and the inversing principle of atmospheric trace gases concen trations is analyzed based on the differential absorption of trace gases.The lin e-shaped absorption spectrum of Hg lamp is introduced into LEDs-DOAS instrumen t to get the instrument function.The standard absorption section of trace gas is convoluted with the instrument function.Then the absorption strength of the tra ce gas is gained by the LEDs-DOAS system.Concentrations of trace gases are retr ieved based on the least-squares fitting method.At last,the NO_2cells are al so used to test the accuracy of the LEDs-DOAS system.Experimental results show that the measuring relative error is less than 5%,which demonstrates that the li ght-emitting diode as a light source of LEDs-DOAS system is feasible and relia ble to measure the atmospheric trace gases.