Numerous environmental factors, such as light and temperature, vary a lot with water depth and these factors to a large extent determine the performance of plants. Therefore, water depth may affect the physiological and biochemical characteristics of submerged macrophytes, including leaf carbon, nitrogen and phosphorus stoichiometric characteristics and photosynthetic pigments composition. In order to examine how submerged macrophytes respond to water depth, we measured these parameters of four submerged macrophytes along water depth in Lake Erhai. Our results show that:responses of the measured parameters of macrophytes to water depth were species-specific; the leaf nitrogen contents of Vallisneria natans, Potamogeton maackianus, Potamogeton lucens and leaf phosphorus contents of V. natans, and P. lucens were positive correlated with leaf chlorophylls; both leaf nitrogen and phosphorus content of V. natans increased with water depth. The mechanism behind the increase of nitrogen content in leaves with water depth may be that V. natans produced more chlorophylls and protein to adapt to the low light levels at deeper sites, while increase in phosphorus content of V. natans was affected by other processes besides adapting to low light.