Abstract: Choosing closed plateau lake Tengchong Beihai wetland leeks as research object. The leaf anatomical structure, photosynthetic physiological characteristics and the correlation between leaf stomata, veins and photosynthesis of amaranth under different water levels were analyzed, and the water-carbon coordination and hydraulic balance of Brasenia schreberi were revealed. The results show that the highest values of pore length, width, area and pore length of B. schreberi appear in the low water level gradient, and the lowest value appear in the deep water level gradient, while the stomatal density and leaf vein density are opposite. B. schreberi has higher net photosynthetic rate, transpiration rate and light energy utilization rate at low water level, while deep water level has higher water use efficiency, and the strong light utilization ability and photosynthesis potential of deep water B. schreberi are at a weak level. There is a linear correlation between the stomatal density of B. schreberi and its photosynthetic gas exchange parameters, and there is a synergistic relationship between stomatal and vein veins, indicating that the leaf veins of B. schreberi provide important support, wind and wave resistance.