Water and heat & CO_2 exchanges between alpine wetland and atmosphere are main causes of the regional climate change. In this paper, the energy and mass exchanges between the alpine wetland and atmosphere have been explored by using the datasets collected from the land surface process field experiment conducted from 16 July to 16 October, 2013 in the source region of the Yellow River. The diurnal characteristics of the sensible heat and latent heat & CO_2 fluxes had been analyzed by statistical methods, the energy closure had also been analyzed. The results have shown: The diurnal variations of the sensible and latent heat fluxes in alpine wetland revealed diurnal characteristics every months, the sensible and latent heat flux increased after sun rise, the peak value of sensible heat flux appeared around 12:0016:00 and reached 150.0 W·m~(-2), the latent heat flux appeared around 16:00 in July, and reached 300.0 W·m~(-2). During the whole summer period, the latent heat was the main consumption of net radiation in the wetland system. The energy closure reached 48.8%. The CO_2 exchange flux displayed a "U" pattern during the whole growing period, the CO_2 flux was downward after sun rise, and reached a peak in the middle daytime, the minimum value was -0.55 mg·m~(-2)·s~(-1) at 15:30 on 21 July. Further analysis has shown that CO_2 flux was controlled by air temperature, solar radiation and canopy.