Abstract: Based on the ORAS5 reanalysis dataset, we analyzed the changes in poleward Atlantic Water (AW) ocean heat transport (OHT) and Pacific Water (PW) OHT via the Bering Strait, Fram Strait and Barents Sea Opening during 1979-2023, and also investigated the correlation between poleward OHT and downstream ocean temperature. The results show that total OHT into the Arctic Ocean through the three gateways has a significant increasing trend ((8.88±2.64) TW·(10 a)^–1) from 1979 to 2023, among which AW OHT via the Barents Sea Opening has the largest increasing trend ((4.89±1.71) TW·(10 a)^–1), and PW OHT through the Bering Strait has the smallest increasing trend ((0.81±0.61) TW·(10 a)^–1). The trends of OHT through the three gateways show significant seasonality. Regional sea water temperature in the Arctic Ocean is significantly correlated with the changes in poleward OHT. The increase of AW OHT through the Barents Sea Opening could lead to the rise of sea water temperature in the Barents Sea in the same year and the next year. The changes of AW OHT through Fram Strait mainly affect the sea water temperature in the intermediate layer of the Eurasian Basin, where the influence gradually expands from the northern edge of the Franz Josef Land at the same year to the entire Eurasian Basin in the lead of 4-7 years. Meanwhile, the changes of PW OHT through the Bering Strait mainly affect the sea water temperature in the Chukchi Sea and the East Siberian Sea in the same year.