[Objective] The temporal-spatial variation of soil moisture and its influencing factors for semi-arid alpine desert communities of Hippophae rhamnoides were studied in order to provide a scientific basis for the restoration of ecosystems of Qinghai Lake and semi-arid deserts. [Methods] H. rhamnoides plantations were taken as the research object. In the growing seasons of 2020 and 2021, vegetation investigation and soil sampling was carried out on the H. rhamnoides communities in the Ketu sandy land on the eastern shore of Qinghai Lake. Through the use of classical statistical methods, the vegetation characteristics of H. rhamnoides and the temporal-spatial changes of soil moisture in different dune geomorphic parts were comprehensively analyzed. [Results] ① In terms of vegetation growth, plant height of H. rhamnoides planted in 2008 (08SJ) was the tallest, followed by plant height in 1987 (87SJ). Plant height in 2015 (15SJ) was the shortest. Vegetation coverage followed the order of 87SJ>15SJ>08SJ. ② Soil moisture content of H. rhamnoides communities followed the order of 87SJ>08SJ>15SJ. Among these communities, the soil moisture contents of the H. rhamnoides planted in 1987 (87SJ) and the H. rhamnoides planted in 2015 (15SJ) were the highest on the windward slope, while the soil moisture content of the H. rhamnoides planted in 2008 (08SJ) reached the maximum value on the leeward slope; ③ Soil moisture content showed obvious seasonal variation, and the soil moisture content was the lowest in the vigorous growth period, and highest at the end of the growing season. ④ Soil moisture content was highest in the 0—20 cm soil layer, and changed little below a depth of 60 cm. [Conclusion] Vegetation distribution pattern, precipitation, and its seasonal changes were the main factors affecting the temporal-spatial variation of soil moisture under H. rhamnoides communities in a semi-arid alpine desert ecosystem.