Li Ch�ngqi�n (李承乾) (619 - October 1, 644) was the original crown prince of Emperor Taizong of Tang China, but was replaced later by his younger brother Li Tai. His courtesy name was Gaoming (高明).

He was named after his birthplace, Chengqian Hall (殿), and became the crown prince on October 8, 627 at the age of eight, after his father became the emperor on August 9. After September 630, his grand teacher (太師) was Li Gang (李綱); on May 6, 632, Li Gang died and was replaced by Yu Shining (於志寧) and Li Baiyao (李百藥). Kong Yingda (孔穎達) and Zhang Xuansu (張玄素) were his live-in scholars (宿儒). Taizong described his son as "understanding of the rituals" (頗識大體).

In 632, with the excuse of the foot illness, he stopped attending court sessions and started to wander around the city engaging in amorous acts and imitated the practices of non-Han "barbarians". His brother Tai began to gain the favor of Taizong.

Li secretly housed a female musical performer called Chengxin (稱心樂伎), but Taizong ordered her killed later. After Chengxin's death, Li was overwhelmed with grief for months, never attending courts, and arranged the failed assassinations of Yu Shining and Zhang Xuansu, who advised him constantly to get over the pain.

On April 6, 644 (Zhenguan 17), after a failed rebellion, he lost his royalty status in Imperial Decree which Deposes Crown Prince Chengqian as a Commoner (廢皇太子承乾爲庶人詔). He died later in the same year in Qian Prefecture (黔州) at the age of 25. The cause is unknown.

He was survived by a grandson, Li Shi (李適), who later pled to Emperor Xuanzong that his grandfather be buried in Zhao Cemetery (昭陵). Li Shi's wish was granted on December 8, Kaiyuan 25, after Li Chengqian was given the posthumous name of Prince Mǐn of H�ngshan (恒山湣王) August 27 the year before. However, it wasn't until May 29, Kaiyuan 26 that Li Shi moved his grandfather into Zhao Cemetery. New Tang Book recorded the burial to be very elaborate, but when the 30 x 3.1-metre tomb was excavated in 1972, it was not found to be the case. There were only 118 characters in his biography memorial tablet (墓誌) and 234 in seal script on his tombstone.