The invention discloses an active solar system optimization method suitable for a building in a cold plateau area. The active solar system comprises a solar photothermal unit and a solar photovoltaic unit, wherein the solar photothermal unit provides a heat source for winter heating of the building through solar heat collection and an auxiliary heat source of an air source heat pump; the solar photovoltaic unit provides a power supply to a building electric appliance, the air source heat pump and a conveying water pump through photovoltaic power generation; and the solar photothermal unit and the solar photovoltaic unit are both arranged on a roof of the building. Aiming at the resource, weather and building characteristics of the cold plateau area, the invention proposes a proper building active solar utilization system, and uses the system coupling relation and the energy flow balance restraint condition for building a system optimization solution model based on the economy and the energy saving property to provide support for comprehensive application of multiple solar technologies to the building in the cold plateau area, so that the application of a solar compound system is promoted.