Abstract: An online extraction of sunflower seed husk electrospray detection device was established. The sunflower seed husk was used as both sample extraction device and spray device. The sample extraction and electrospray mass spectrometry were combined organically, and the components in the sample were extracted and directly sprayed for detection without sample pretreatment, which greatly improved the detection efficiency. The melamine in milk powder, atrazine in soil, and α-caconine in potato were analyzed. The peaks of melamine and atrazine were good, and the lowest concentration detected reached 0.01 mg/kg. Because the sunflower seed husk was essentially an "electrophoresis pool" in a high electric field, and substances with different charges moved in the opposite direction, so that the target compound was desorbed from the matrix and was quickly extracted by the solvent, and this was the reason for its high sensitivity. The α-calconine in different positions of potato was detected, and a line graph was drawn according to the sampling position and signal intensity to analyze the spatial distribution of α-calconine in potato. It was found that the signal was the strongest in the sprouting area on the epidermis, and the signal strength gradually weakens as the distance became longer. Secondly, the signal intensity of the internal of potato decreased faster than the surface. The limit of detection reached 0.001 g. This method can not only quickly extract and detect target compounds of complex matrices samples, but also has application potential in mass spectrometry imaging.