Abstract: Focusing on the long circulating preheating time and large steam consumption of dual horizontal wells during the start?up phase by steam assisted gravity drainage (SAGD) process, this paper introduces the mechanisms of 4 fast start?up technologies of SAGD process for dual horizontal wells, which include solvent assisted start?up, foam assisted start?up, electromagnetic heating start?up and stress expanding start?up, and also analyzes each advantages and existing problems in their applications. It is suggested that the stress expanding startup technology has obvious advantages and further related researches should be made to improve its technical adaptability, and the combination of these fast start?up technologies will be an effective way for improving the effects of start?up phase．