Purpose: The purpose of this study was to investigate the effect of 4 weeks Passive Repetitive Isokinetic (PRI) training on knee extensor isokinetic strength in elite female athletes. Methods: Eight elite female volleyball players (mean age 19.43±1.27 years, stature 167.86±3.98 cm, and body mass 58.43±9.57 kg) and seven elite female handball players (mean age 20.71±1.25 years, stature 166.14±3.76 cm, and body mass 60.71±8.81 kg) were assigned to PRI training and traditional resistance training for 4 weeks of training at 3 time per week. Before and after training, the torque of knee extensor at 0, 60, 120, and 180°/s were measured by using Biodex System III dynamometer. Results: after 4 weeks training, the PRI training could significant improvement in isometric torque about 12.24%, in 120°/s concentric torque about 10%, in 60°/s eccentric torque about 27.61%. Moreover, the increase percentage of PRI training was higher than traditional resistance training does. Conclusions: 4 weeks PRI training increased knee extensor of elite female athletes in isometric strength, in high contraction velocity of concentric strength, in eccentric strength. The findings suggested that PRI training is an effective method for increasing muscle strength and power. The PRI training appropriated some sport events that related to speed or power, such as volleyball, due to the characteristic of its training movement is similar with real sports.