The quality of compaction is important to Hot Mixed Asphalt (HMA) pavement. Most premature failures of asphalt pavement are concerned with poor compaction. Characteristics of cooling curve of asphalt mixture were studied in this paper. Through on site measurement, it was found that air temperature, solar radiation, wind velocity and layer thickness had great influence on cooling time. Then, with ABAQUS finite element software, the rule of HMA mixture cooling curves during paving was simulated. A simple multi-factors regression equation was given which can be used to estimate the effective compactible time.