The invention belongs to the related field of indoor ventilation and air purification, and discloses a positive-pressure control system applicable to area air purifying. The positive-pressure control system comprises a primary air purifying module, a header fan, a medium-high-efficiency air purifying module, a controlled area, an electric air valve and a one-way valve which are sequentially connected to form a closed-loop air system. The positive-pressure control system further comprises a fresh air fan, an outlet of which communicates with the outlet of the one-way valve and the inlet of the primary air purifying module, a second flow sensor which is arranged at the outlet of the fresh air fan, a first flow sensor which is arranged at the outlet of the one-way valve, a first pressure which is arranged at the outlet of the electric air valve, a second pressure sensor which is arranged in a controlled area, and a control assembly. The control assembly is used for controlling degree of opening of the electric air valve to regulate the positive-pressure value in the controlled area, and is further used for controlling rotation speed of the fresh air fan, so that the positive-pressure value in the controlled area is kept stable.