Abstract: Utilizing EAM potential,Al single crystal with molecular dynamicssimulation method was studied. Under mode Ⅰ and Ⅱ loading, the influence of temperature and loading rate on dislocation emission and the criticalstress intensity factor was analyzed.The simulatedresults show that the critical stress intensity factor for dislocation emission decreases exponentiallyas the temperature increases. Loading rate will influence the critical stress intensity factor to some degree. The critical stress intensity factor will increase as loading rate increases.