An experiment was made to analyze the influence of CO_2 concentration and atmospheric rising to potato growth in the semiarid region of Loess Plateau. During the experiment, the morphology structure, stem tuber formation, water content physiology, ecology and carbon exchange were observed. The collaborative influence of elevated CO_2 concentration and atmospheric warming on potato photosynthetic physiology ecology, as well as the characteristic of leaf's photoresponse process and yield formation in the semi-arid region of Loess Plateau was studied based on a parallel observation on meteorological element. The result showed: the precipitation in the experiment region decreased in 19582016, with a decreasing rate of -12.17 mm·(10 a)~(-1); the air temperature rose significantly in recent 59 a, the climatic tendency rate of linear regression was 0.42 ℃·(10 a)~(-1); the temperature had kept rising since 1980s, and the rising was especially significant after 2000. When potato was treated by warming and CO_2 concentration elevating during the growing stage, it could be found that the net photosynthesis rate of potato leaves was improved and higher than that of the control group and group of potatoes treated in other ways; during the late growing stage, the net photosynthesis rate of leaves treated by warming and CO_2 concentration elevating decreased more quickly. As the ambient CO_2 concentration increased, the leaf stomatal conductance gradually decreased, and the stomatal conductance of leaves treated by warming and CO_2 concentration elevating during the growing stage was lower than control group. The leaf transpiration rate increased with warming, which was higher compared to control group and group treated in other ways, in the early growing stage, meanwhile, the transpiration rate became lower in the late growing stage compared to control group. The water use efficiency of leaves treated by warming and CO_2 concentration elevating was distinctly improved and higher than control group and group treated only by warming. Under the background of warming and CO_2 concentration elevating, the threshold of photosynthetic active radiation flux density can be increased when the assimilation of photosynthesis is equal to the respiration consumption during the photosynthesis process of potato leaves. Photosynthesis ability as well as maximum synthesis ability increase under weak light conditions, while the threshold of photosynthetic active radiation flux density increase when assimilation of photosynthesis reached maximum value. The coordinating influence of warming and CO_2 concentration elevating to some extent can relieve the influence of dark respiration rate caused by warming. The actual yield of potatoes treated by warming and CO_2 concentration elevating was distinctly higher than control group and group treated only by warming. The yield of potatoes treated only by warming was relatively lower, which indicated that in the semi-arid region of Loess Plateau, warming went against the expansion of potato stem tubers. Warming during the stem tuber expansion stage would delay the potato tuber growth and deform the tubers. Therefore, warming synchronized with CO_2 concentration elevating will improve the net photosynthesis rate and water use efficiency of potato leaves, promote the dry matter accumulation and increase the yield.