Abstract: In the more than 20 years after disintegration of the Soviet Union, the remaining historical issues and conflicts caused by the construction of a new nation have always plagued Uzbekistan and Tajikistan. In the era of Karimov,the conflicts were continuously intensifying between Uzbekistan and Tajikistan centering on issues such as borders, territories, nations, natural gas, water resources, so that there may even be military conflicts. Since president Mirziyoyev took office in late 2016, the relations between Uzbekistan and Tajikistan have shown significant improvement. Factors driving the continuous improvement of bilateral relations are:their similar national cultures,Tajikistan's demand for developing friendly relationship with Uzbekistan to overcome its domestic inefficient transportation, President Mirziyoyev's devotion to improve relations with neighboring countries to create a favorable external environment for domestic economic development,and games between superpowers outside the region.

Key words: Karimov, Mirziyoyev, Uzbekistan, Tajikistan, the Belt and Road, central Asian relations