Abstract: Leymus racemosus is a close relative of wheat and plays important roles in wheat improvement. A series of wheat-L.racemosus addition lines and substitution lines had been produced. There is less report about the study on the effects of exogenous chromosomes of L. racemosus on photosynthesis and yield character. Understanding its character of the chromosomes harboring the useful genes would provide information for transformation or introgression of genes. Net photosynthetic characteristics of 10 Chinese Spring- L. racemosus addition lines and substitution line and their wheat background Chinese Spring were studied at the stage of early filling by Photosynthesis System, and the yield traits were investigated after harvest. The results showed that photosynthetic rate were lower of the 10 lines were lower than Chinese Spring, but most of the difference was not significant. Chromosomes E had Positive effect on water use efficiency. Chromosome E, J could increase wheat grain weight per spike and 1000-grain weight. The addition lines with high grain weight could be used for breeding.