The invention discloses combined use of a tetravalent cisplatin predrug and a biological reducing drug. The structural f formula of the tetravalent cisplatin predrug is represented by a formula (I) (shown in description), wherein m represents 0-1000, n represents 1-1000, and I represents 1-1000. The tetravalent cisplatin predrug is loaded with a biological reducing drug, namely tirapazamine, a cisplatin anti-cancer drug is released through degradation in a tumor microelement,and the high expression of enzyme families of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) in cancer cells can be induced, so that the oxygen consumption rate of the cancer cells is increased, the pesticide effect of the biological reducing drug, namely tirapazamine is further improved, and the treatment effect of the whole cancer treatment process can be improved through synergistic treatment.