The invention discloses a method for processing a contact surface of a release capsule with an object to be tested. The method comprises the following steps: (1) all parts are made by machining stainless steel or glass, for the stainless steel parts, the procedures of firstly oxidizing with acid and then cleaning with an organic solvent and water or the procedures of performing electrolysis after oxidation and then cleaning with the organic solvent and water are adopted, and for the glass parts, the procedure of corroding with HCL or HF or roughing the surfaces of the parts by using a physical method is adopted; and (2) a deactivation layer is processed on the surface of each part cleaned in (1), or a middle layer is processed on the surface of each part cleaned in (1) and then the deactivation layer is processed on the surface of each middle layer. According to the method, the surface adsorptive force is reduced, the object to be tested, which is adsorbed onto the inner wall of a capsule body and the contact surface of each part with the object to be tested, can be reduced greatly, so that a detection value of a sample obtained from a sampling pipe is closer to an actual value of the objected to be tested in the capsule body, and the detection precision of the release capsule can be increased effectively.