Terahertz waves (THz,T-ray) lie between far-infrared and microwave inelectromagnetic spectrum with frequency from 0.1 to 10 THz. Many chemical agentexplosives show characteristic spectral features in the terahertz. Compared withconventional methods of detecting a variety of threats, such as weapons andchemical agent, THz radiation is low frequency and non-ionizing, and does notgive rise to safety concerns. The present paper summarizes the latest progress inthe application of terahertz time domain spectroscopy (THz-TDS) to chemical agentexplosives. A kind of device on laser radar detecting and real time spectrummeasuring was designed which measures the laser spectrum on the bases of Fourieroptics and optical signal processing. Wedge interferometer was used as the beamsplitter to wipe off the background light and detect the laser and measure thespectrum. The result indicates that 10 ns laser radar pulse can be detected andmany factors affecting experiments are also introduced. The combination of laserradar spectrum detecting, THz-TDS, modern pattern recognition and signalprocessing technology is the developing trend of remote detection for chemicalagent explosives.