The invention discloses a purification type capacitor device for determining physiological dielectric characteristics of wheat leaves. A cuboid-shaped or cylindrical shell body covers a cuboid-shaped or cylindrical box body; furthermore, the cuboid-shaped or cylindrical shell body is connected to a vertical plate through a connection part; the device further comprises a purification device; a gas inlet groove is connected with a mini-type ventilation fan through a first channel; a groove channel is internally equipped with a part with wiping lint; the groove channel is connected with a screen mesh through a third channel; the third channel is located in the first channel. The defects that the erection between the shell body and the box body increases the difficulty, the shell body is commonly damaged after the service life of the shell body is not short, the erection reliability is difficult to guarantee, a blade clamping device is usually polluted by suspended particle impurities during a working period, the cooling of the blade clamping device is interfered, the temperature is usually too high so that the blade clamping device stops working, and a chip has faults, even the blade clamping device is damaged are avoided.