The invention belongs to the technical field of metallic material surface treatment, and relates to a recovery and reuse method of cobalt salt chemical oxidation waste liquid. Specifically, the recovery and reuse method of the cobalt salt chemical oxidation waste liquid comprises the following steps: 1) sediment in the cobalt salt chemical oxidation waste liquid is removed after filtration; 2) a pH value of filtrate is adjusted to 6-9; 3) an oxidizing agent is added and cobaltous ions are oxidized into cobalt ions; and 4) liquid obtained in the step 3) is mixed with new-made cobalt salt chemical oxidation liquid according to a certain volume ratio, and then mixed liquid is used. With the adoption of the preparation method, a chemical conversion film having better corrosion resistance can be prepared, the operation is simple and easy to carry out, and industrialized popularization is facilitated. Through the recovery and reuse of the cobalt salt chemical oxidation waste liquid, the recovery cost is reduced and a resource utilization rate is raised from the economy aspect; and from the environment aspect, harm to the environment is reduced, no environment-hostile materials are produced in a recovery process, and the green and environmental protection requirements are met.