To overcome the problems of insufficient natural lighting and weak light comfort for traditional residential buildings in Tibet, a design method for a feasible multifunctional window system is proposed. The novel system is mainly composed of a photovoltaic power generation panel, reflective panel, thermal insulation panel, and rotating shaft. Based on the above method and for typical cases, a theoretical analytical model of multifunctional windows was established in 3 operational patterns: summer, winter, and transitional season, and field tests were conducted for verifying the data accuracy. The results show that, compared with the same size traditional window, a multifunctional window increases southern indoor natural lighting depth by 5 times for 10 h in the transition season, increases the lighting depth by 2.5 times (above 7.5 m) for 9 h in winter, and increases daylight factor by 0.5% in summer; the average monthly power generation of photovoltaic power generation panel in summer is 9kW·h, and the annual photovoltaic power generation reaches up to 90kW·h. The multifunctional window increases the temperature difference between the inner and outer surfaces of the window in winter and summer by about 3～8 ℃ and 2～4 ℃, respectively,and reduces the temperature difference between the inner surface of the window and wall by about 2～4 ℃ in winter,and the inner surface temperature of the window is closer to the indoor temperature. Overall, the multifunctional window has the characteristics of low cost, diverse functions, remarkable effect, and strong economic competitiveness. It is of important significance in other advanced window designs and practical applications. It can be directly applied in the repair of the old building window as well as the new ones in the Tibet rural area.