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Tree water transport and utilization are essential for maintaining ecosystem stability in seasonally arid areas. However, it is not clear how <i>Platycladus orientalis</i> absorbs, consumes via transpiration, and stores water under varying precipitation conditions. Therefore, this study used stem sap flow thermal dissipation probes and hydrogen and oxygen isotope tracing technology to observe different water control treatments in a <i>P. orientalis</i> plantation. We found that the average daily sap flow of <i>P. orientalis</i> under different water control treatments had the following order: no rainfall (NR) < half rainfall (HR) < double rainfall (DR) < natural rainfall (AR). The percentage of nocturnal sap flow was as follows: AR (13.34%) < NR (19.62%) < DR (20.84%) < HR (30.90%). The percentage of water storage was NR (4.13%) < AR (4.49%) < DR (6.75%) < HR (9.29%). The sap flow of <i>P. orientalis</i> was primarily affected by vapor pressure deficit and solar radiation, with a degree of influence of DR < NR < HR < AR. The response of <i>P. orientalis</i> sap flow to environmental factors differed due to the soil changes in relative extractable water (REW) before and after precipitation. During high REW conditions, environmental factors have a higher impact on sap flow. The source of water absorbed changed regularly with the precipitation gradient. When soil water content increased, the water source used by <i>P. orientalis</i> gradually changed to shallow soil. Compared to before and after precipitation, there was no significant change except for NR. <i>P. orientalis</i> could regularly adjust the activities of transpiration water consumption, water storage, and absorption. This adaptive property is conducive to survival through extreme drought stress.