Watermelon was introduced into Khitan from the Uighurs. However，there is a controversy about which “Uighur” refers to. Previously，the academia thought the “Uighur” watermelon came from Bešbalïq of Qočo Uighur Kingdom. Recently，some scholars disagree with this opinion. They think that watermelon could never come from the Qočo Uighur Kingdom，but should come from Mongolia. However，watermelon likes dry and hot climate，while Mongolia is very cold；watermelon likes sandy soil，but Mongolia is dry grassland soil. Both climatic and soil conditions are not suitable for watermelon. According to historical records，the land was empty after the Uighur moved westward in 840. Since it is uninhabited，watermelon cultivation cannot be talked about. According to Dunhuang manuscripts and Turpan murals，it can be known that watermelon cultivation in Qočo Uighur Kingdom should be relatively widespread. Some people deny that the main evidence that the watermelon came from the Qočo Uighur Kingdom is that Taizu of the Liao Dynasty，namely Yelü Abaoji，could not reach Futu City in Bešbalïq. In fact，it was a misunderstanding of the history books. Standard History of Liao Dynasty clearly records that Taizu of Liao sent troops to attack Futu City and had garrison in the area of Barkol Mountain.