In order to explore the photosynthetic physiological characteristics of different trees, shrubs, herbs in Helan Mountain and their adaptive characteristics and mechanisms to the natural environment, we used a Li6400XT portable photosynthesis instrument to determine the gas exchange parameters and natural environmental factors of ten types of trees, shrubs and herbs in Helan Mountain and analyzed their correlations. The results show that: (1) the daily mean value of net photosynthetic rate (P_n) changed in a rank of Thermopsis lanceolata>Ulmus glaucescens>Populus davidiana>Cotoneaster hissaricus>Agropyron cristatum>Pinus tabuliformis>Lonicera microphylla>Berberis thunbergii>Picea crassifolia>Carex muliensis, and from the perspective of different life types, it was represented as tree > herb > shrub. (2) The diurnal variation curves of P_n of P. crassifolia, P. tabuliformis, U. glaucescens, B. thunbergii, C. hissaricus and L. microphylla were single peaks, while the Pn diurnal curves of P. davidiana, T. lanceolata, C. muliensis and A. cristatum were double peak shape, with obvious photosynthetic “noon break” phenomenon. The phenomenon of P. davidiana and A. cristatum were mainly caused by nonstomatal factors, while T. lanceolata and C. muliensis were mainly caused by stomatal factors. (3) Compared with other plants of the same life type, P. crassifolia, P. tabuliformis, L. microphylla and T. lanceolata had higher daily mean water use efficiency (WUE). (4) Path analysis showed that light intensity (PAR) was the main determinant factor for trees and shrubs, while leaf temperature (T_l) and saturated vapor pressure deficit (VPD) were the main limiting factors.The main limiting factors for herbaceous plants were air temperature (T_a) and T_l. The study suggested that diurnal variations of photosynthetic characteristics of different arborshrubgrass in Helan Mountain show different patterns. Compared with other plants of the same life type, P. crassifolia, P. tabuliformis, L. microphylla and T. lanceolata have better drought resistance and can adapt to relatively dry climate environment.