The invention provides a cis-platinum complex, and also relates to a synthetic method of the cis-platinum complex and an application of the cis-platinum complex in preparing nucleotide and protein probes. The cis-platinum complex can be connected with fluorescein, and can also be firmly connected with DNA, RNA and proteins, so that the cis-platinum complex can be used as a connection main body of the biological probe and is suitable for marking and detecting the target DNA, RNA and protein; the cis-platinum complex is simple in marking operation procedures, and is not limited to the size of a marking molecule and not limited to a pH value of a marking mixed system; the cis-platinum complex can be widely applied to the subdivisions such as nucleotide, protein (antibody) and protein micro arrays, hybridization of comparative genome and the like; in addition, the marking efficiency is significantly improved, the marking time is shortened, the fluorescent intensity stability is improved, and the marking effect is excellent; and therefore, the application prospect in the fields such as preparation of nucleotide and protein probes, research and development of biological medicine, diagnosis of diseases and the like is good.