Abstract: To explore the physiological response of kentucky bluegrass (Poa pratensis L.) to the inoculation of Rhizoctonia solani, two kentucky bluegrass cultivars,‘Midnight’and‘Blue Peacock’ , which have exhibited resistant and susceptible to Rhizoctonia solani were inoculated by Rhizoctonia solani. During the inoculation period, the disease incidence and disease index were calculated and the relative conductivity, contents of MDA, proline and chlorophyll in the leaf tissues of turfgrasses were tested and analyzed comparatively. The results indicated that some parameters including disease index, relative conductivity, contents of MDA, proline and chlorophyll increased after inoculation while chlorophyll content gradually decreased compared to no-inoculation. During the 7 days after inoculation, disease index, relative conductivity, contents of MDA and proline increased higher in‘Blue Peacock’than that in‘Midnight’ . Moreover, the degree of reduction of chlorophyll content was higher in‘Blue Peacock’than that in‘Midnight’ . Correlation analysis showed that significant positive correlation were found between contents of MDA, proline, relative conductivity and the change of disease index, whereas significant negative correlation were exhibited between chlorophyll content and the change of disease index.