The invention discloses a barium carbonate electrolytic dissolution device, aiming at dissolving barium carbonate in an electrolytic way so as to be combined with an ion chromatography for trace negative ion measurement. The barium carbonate electrolytic dissolution device comprises a creepage pump and an electrolytic tank, wherein the electrolytic tank comprises a negative electrode chamber, a positive electrode chamber and a cation exchange membrane; the negative electrode chamber and the positive electrode chamber are respectively formed by gaps between two corrosion-resistant films and the cation exchange membrane; the positive electrode chamber is provided with a sample pool. The invention also discloses a detection method of the barium carbonate electrolytic dissolution device. According to the barium carbonate electrolytic dissolution device, electrolysis is directly adopted instead of conventional acid dissolution, so that the introduction of impurity ions can be avoided; after being dissolved, the sample is directly injected, so that the trace negative ions in the barium carbonate can be detected, and the application scope of ion chromatography is expanded. Furthermore, water is taken as electrolyte solution, so that the barium carbonate electrolytic dissolution device is cleaner and free from pollution, and aftertreatment is more convenient.