Platinum complexes containing 3-ketone cyclobutane 1,1-dicarboxylic acid as leaving group for treating cancers and a preparation method of the complexes, one of the platinum complexes is cis-[3-ketone cyclobutane-1,1-dicarboxylic acid radical.diamineplatinum (II)], GSH-5 for short, the chemical structure formula is expressed by formula (1). The other platinum complex is cis-[3-ketone-cyclobutane-1,1-dicarboxylic acid radical.trans-1,2-cyclohexanediamineplatinum (II)], GSH-6 for short, the chemical structure formula is expressed by formula (2). In the formula (2), two chiral carbon atoms marked with * in the trans-1,2-cyclohexanediamine group are both of R forms or S forms.