The system leakage rate of sintering belt cooler in a steel plant is serious and the heat of circulating hot air is not fully utilized, resulting in low efficiency of waste heat recovery. It is proposed to optimize the access point of circulating hot air while to strengthen the seal, and the numerical simulation of the cooling process of sinter under different optimization schemes is carried out. The results show that the solution of supplying the 150 ℃ hot air from the circulating fan to the 1st blast box with the highest sinter temperature and connecting the original blower of the 1st blast box to the original circulating hot air access point of the 2nd blast box has the most obvious effect in waste heat recovery, which can increase the waste heat recovery from 428. 65 MJ/t to 506. 12 MJ/t with an increase of 18. 08%, and the solution can reduce the temperature difference at the beginning of sinter heat exchange, which can improve the yield and metallurgical performance of sinter. The results can provide a basis for improving the waste heat recovery effect of circulating hot air in the blast box access method of sintering cooler.