The present disclosure relates to a system, a method, a device, and an electronic atomizing device for detecting a nicotine content in an e-liquid. The system includes: a sampling circuit configured to acquire characteristic parameters, and the characteristic parameters being configured to calculate an impedance of the e-liquid in an e-liquid containing component; and a controller electrically connected to the sampling circuit, configured to calculate the impedance of the e-liquid according to the characteristic parameters fed back by the sampling circuit, and determine the nicotine content in the e-liquid according to the impedance of the e-liquid and a preset corresponding relation between the impedance and the nicotine content.