Low temperature cracking and damage of asphalt pavement is very common, the asphalt bending beam rheometer(BBR) test proposed by SHRP to evaluate the phenomenon of low temperature cracking is still widely used. In order to better evaluate the asphalt physical hardening of one of the main factors of early cracking of asphalt pavement, extended bending beam rheometer(EBBR) test was used to evaluate ten kinds of commonly used road asphalt, and the low temperature grade loss index was calculated from the test results. Asphalt creep stiffness and creep rate at different low temperature conditioning period were measured, and Avrami isothermal crystallization dynamics theory was used to do fitting analysis, so the asphalt binder physical hardening mechanism can be studied. The results show that the EBBR method is more accurate than the BBR method for evaluating the low temperature performance of the asphalt, and the changes of Avrami index obtained by the fitting analysis of isothermal crystallization data can distinguish the low temperature physical hardening of the different asphalt from the same low temperature grade loss value obtained by the EBBR test, and the performance of asphalt physical hardening and crystallization can provide more accurate information about the anti cracking ability of pavement asphalt.