An infrared differential thermal detector for asphalt pavement permeability is developed. The detector is based on a high speed infrared detector system and a software system including infrared surface temperature measurement, signal conversion, chromatography, etc. It is the first infrared differential thermal detector which can continuously operate at a speed of 100 km/h in the field of asphalt pavement permeability measurement. The research result shows that it is feasible to evaluate the permeability of asphalt pavement by measuring the surface temperature difference of asphalt pavement with the infrared temperature measurement technology. Compared with the traditional fixed-point permeability detector, its detection effectiveness is improved by a factor of 50 and its correlation coefficient is up to 0.8985. Because the system can share the pavement permeability information with an intelligent fog seal asphalt distributor, it can form a complete asphalt pavement permeability treatment technology which meets the requirements of different highways in China.