Two wheat cultivars（Triticum aestivum L.）that differ in their sensitivities to infection (MX146：sensitive, and 88375：tolerant) were infected by Puccinia striiformis and used to evaluate the relationship between pathogen infection and host photosynthesis functions by measuring photo-synthesis constant, chlorophyll content, photosynthetic electron transport rate and expression of protein D1 of photosystem II reaction centers. We found that net photosynthetic rate and chlorophyll content decreased in the infected sensitive wheat cultivar, while both net photosynthetic rate and the chlorophyll content of the tolerant wheat has a recovery process. In infected sensitive wheat, the electron transport rate of PSII was similar to that of whole chain which was inhibited by pathogen infections, but less influence shown on electron transport rate of PSI. Whereas in infected tolerant wheat, the effects of infection on electron transport rate were minor. The protein D1 content variance always showed similar or proportional trend to that of PSII electron transport rate, indicating that suppression of D1 expression is a possible cause for the inhibition of PSII electron transport.