Preparation method of potassium chloroplatinite

The invention discloses a preparation method of potassium chloroplatinite. The preparation method comprises the following steps of: (1) putting spongy platinum and nitromurlatic acid to a reactor, heating to 100 DEG C and reacting to prepare a chloroplatinic acid solution; (2) adding a 10% oxalic acid solution to the chloroplatinic acid solution in the step (1), and reducing to generate a chloroplatinous acid solution; and (3), adding a saturated potassium chloride solution to the chloroplatinous acid solution in the step (2) to generate the potassium chloroplatinite, wherein the reaction temperature in the step (2) is 50-60 DEG C, the reaction temperature in the step (2) is 50-60 DEG C, and reactions of all steps are carried out in the same reactor, wherein the weight ratio of the platinum to the nitromurlatic acid to the oxalic acid to the potassium chloride is 1: (8-10): (0.64-0.66): (0.76-0.8). The potassium chloroplatinite prepared by using the method disclosed by the invention has the advantages of low cost, low pollution and simpleness in operation.