Zhang Yichao ("Chinese: 張議潮; "pinyin: Zhāng Yìcháo) (張義朝 or 張義潮 or 張議潮) (799?-872) was an ethnic "Han Chinese resident of Sha Prefecture ("Chinese: 沙州; "pinyin: shāzhōu, in modern "Dunhuang, "Gansu). When the "Tibetan Empire plunged into civil war, he led a rebellion, capturing several cities and reverted the area's allegiance to the "Tang Dynasty. He subsequently conquered the "Hexi Corridor and governed it as the military commissioner ("Jiedushi) of "Guiyi Circuit ("Chinese: 歸義軍; "pinyin: Guīyìjūn, headquartered in modern Dunhuang) under nominal authority of the Tang emperors.
Little is known about Zhang Yichao's early life, other than that he was a resident of Sha Prefecture (Dunhuang).
By 851, the "Tibetan Empire which had ruled the southern Tarim Basin and modern Gansu region since 790 was being torn by civil war.
In 848, Zhang secretly planned a rebellion with the other "Han Chinese, "Yugur (Uyghur), "Tuyuhun and "Qiang residents of Sha Prefecture to return Sha Prefecture to Tang allegiance. One day, he led armed soldiers and approached the city gates, and the Han all rose in response. The Tibetan garrisons abandoned the city and fled. Zhang thereafter claimed the title of acting prefect of Sha Prefecture and submitted a petition to "Emperor Xuānzong of Tang, offering his loyalty and submission. Xuānzong thus made him Official Guard (防禦使, Fangyushi) of Sha Prefecture.
Later in the year, Zhang's launched an attack on ten other nearby prefectures with Tibetan garrisons — Gua (瓜州, in modern "Jiuquan, "Gansu); Yi (伊州, in modern "Hami Prefecture, "Xinjiang); Xi (西州, in modern "Turpan Prefecture, "Xinjiang); Gan (甘州, in modern "Zhangye, "Gansu); Su (肅州, in modern Jiuquan); Lan (蘭州, in modern "Lanzhou, "Gansu); Shan (鄯州, in modern "Haidong Prefecture, "Qinghai); He (河州, in modern "Linxia Hui Autonomous Prefecture, "Gansu); Min (岷州, in modern "Dingxi, "Gansu); and Kuo (廓州, in modern Haidong). Afterwards they prepared maps of the 11 prefectures and his brother Zhang Yize (張義澤) submitted them to Xuānzong at "Chang'an to prove their allegiance to the Tang dynasty. Xuānzong named the 11 prefectures Guiyi Circuit (歸義), with its capital at Sha Prefecture, and made Zhang Yichao its military commissioner and his secretary Cao Yijin (曹義金) its secretary general.
In 866, Zhang submitted a report stating that the "Uyghur chieftain Gujun (固俊) had recaptured from the Tibetan Empire Xi Prefecture, Ting Prefecture (庭州, in modern "Changji Hui Autonomous Prefecture, "Xinjiang), Luntai (輪台, in modern "Ürümqi, "Xinjiang), and Qingzhen (清鎮, modern location unknown) — apparently implying that Gujun did so under his command.
In 867, Zhang visited Chang'an and paid homage to "Emperor Yizong of Tang. Yizong made him a general of the imperial guards and kept him at Chang'an. Yizong also commissioned Zhang's nephew Zhang Huaishen (張淮深) to serve as the acting military governor of Guiyi. He died in 872, probably while residing at Chang'an.