Abstract: In order to reduce the irrigation requirements of turfgrass species and increase the utilization ratio of precipatiation in Beijing，the study focuses on the irrigation requirements of typical cool season turfgrass species under full use of precipatiation. The datasets of two cool season turfgrass species, i.e., Kentucky bluegrass and Tall fescue collected in 2003 were used to calibrate the irrigation scheduling simulation model (ISRAEG), and then the datasets of 2004 were used to validate the ISRAEG model. Finally, the ISAREG model was used to simulate the irrigation schedules for the two cool season turfgrass species in dry, normal and wet years with different maintenance levels. The results show that the value of crop coefficient for the cool season turfgrass species in the growing season is ranged in 0.5～1.0. And the irrigation quantity required for Kentucky bluegrass and Tall fescue are 432～682 mm/a and 462～752 mm/a in the highest maintenance level, respectively. Meanwhile, the irrigation quantity required for the cool season turfgrass species are 252～432 mm/a and 312～492 mm/a in the first degree of maintenance level, respectively. The results are expected to provide some scientific implications for the best irrigation management practices of the cool season turfgrasses in Beijing area.