The invention discloses an active-based condensed dew fog water electrical conductivity measuring device, wherein the device includes a condensed dew active acquisition device, an electrical conductivity measuring device and a control device. The condensed dew active acquisition device includes a condensed dew active acquisition chamber, a gas intake port is arranged on the side wall of the condensed dew active acquisition chamber, and a gas intake fan is arranged in the gas intake port; a refrigeration device arranged on the inner wall or the outer wall of the condensed dew active acquisitionchamber is used for reducing the temperature in the condensed dew active acquisition chamber; the electrical conductivity measuring device includes a condensed dew collecting groove, and the condensed dew collecting groove arranged at the bottom of the condensed dew active acquisition chamber is provided with a liquid level switch and an emptying solenoid valve; a probe of an electrical conductivity measuring instrument is arranged in the condensed dew collecting groove; a spray device and a drying device are arranged above the probe of the electrical conductivity measuring instrument and areused for cleaning and drying of the probe respectively; the control device includes a micro control unit MCU and a control circuit connected with an I/O interface of the micro control unit MCU. The device has the characteristics of high degree of automation, high measuring accuracy and the like.