The discovery of Loulan ancient city (LA) in the early 20th century has important significance for understanding the history of Western regions and the Silk Road civilization. The current academic community still has disputes on whether LA was the capital of Loulan Kingdom, the time of its rise, peak and decline, and the process, rate and driving mechanism of human activity change. This study uses the radio carbon dates (¹⁴C) database of LA to reconstruct the history of the rise and fall of human activity, and finds that LA experienced more than ∼500 years from its rise to its peak and then to its decline: 1) the city rose rapidly, and the population increased rapidly from ∼A.D. 0 to 230; 2) the city was prosperous and flourishing, and the intensity of human activity reached its peak from ∼A.D. 160 to 340, especially in ∼A.D. 230, when the population reached its peak; 3) the city accelerated its decline, and the intensity of human activity decreased significantly, and the population shrank rapidly from ∼A.D. 230 to 500; 4) LA was completely abandoned after ∼A.D. 560. The results of the ¹⁴C dating database do not support that LA was the early capital of the Loulan Kingdom. By comparing the human activity record of LA with the existing high-resolution palaeoclimate records in the surrounding mountainous areas of the Tarim Basin and South Asia, it is found that the superposition of centennial-scale westerly circulation strength events and the ∼500-year cycle of the Indian monsoon jointly controlled the precipitation and meltwater (snow) supply of the mountains in the Tarim Basin, affecting the changes of surface runoff and oasis area in the basin, which is one of the important factors causing the rise and fall of LA.

20世纪初楼兰古城的发现对于了解西域历史和丝绸之路文明具有重要意义。目前学术界对于洛杉矶是否是楼兰王国的都城、其兴起、鼎盛和衰落的时间，以及人类活动变化的过程、速率和驱动机制等仍存在争议。本研究利用洛杉矶的放射性碳测年（¹⁴ C）数据库重建了人类活动兴衰的历史，发现洛杉矶从兴起到鼎盛再到衰落经历了约500多年的时间：1 ）从~公元0年到230年，城市迅速崛起，人口迅速增加；2）城市繁荣昌盛，人类活动强度在~公元160年至340年达到顶峰，特别是~公元230年，人口达到顶峰；3）城市加速衰落，人类活动强度显着下降，人口从～公元230年迅速减少到500人；^{4) 公元560年以后，洛杉矶被完全废弃。14C}测年数据库的结果不支持洛杉矶是楼兰王国的早期首都。通过将洛杉矶的人类活动记录与塔里木盆地周边山区和南亚现有的高分辨率古气候记录进行比较，发现百年尺度的西风环流强度事件与~500年周期的叠加印度季风共同控制塔里木盆地山地降水和融水（雪）补给，影响流域内地表径流和绿洲面积的变化，是引起LA升降的重要因素之一。