The invention discloses an electrochemical detection method based on metal ion marking. According to the technical scheme, three methods of the same kind are involved, and the first method as a basicmethod comprises the following steps that 1, an antibody of a to-be-marked object is marked with a metal ion material; 2, another antibody of the to-be-marked object is marked with one of a pair of substances with pathoclisis; 3, nanospheres are marked with the other one of the pair of substances with pathoclisis; 4, electrochemical detection is conducted. In the electrochemical detection method,the electrochemical characteristics of metal ions and the high sensitivity of an electrochemical method to metal ion detection are utilized, an immune complex is marked with the metal ions and collected through the nanospheres, then the nanospheres with the immune complex are enriched onto the surface of an electrode through separation, and the detection sensitivity is greatly improved. The methodis high in stability, high in repeatability and accurate and reliable in result, the aim of quick and sensitive detection is achieved, and the application of the electrochemical detection method based on the metal ion marking in the field of in vitro diagnosis is expanded.