Abstract: This paper has compared the diurnal variation of photosynthesis and transpiration character of Aneurolepidium chinense with that of Puccinellia tenuiflora in Songnen alkalited grassland. The regularitics of their diurnal variation are similar. But the photosynthetic ability and water use efficiency of P. tenuiflora is better than A. chinense. That is one of the reasons why saline-alkali tolerance of P. tenuiflora is better than A. chinense.

Key words: Aneurolepidium chinense, Puccinellia tenuiflora, Photosynthesis and transpiration character, Diurnal variation