The invention relates to a pickling agent for chromium stainless steel, in particular to a direct pickling agent for chromium stainless steel. The method solves the problems that the existing pickling agent for removing chromium stainless steel oxide scale is unreasonable, and thus pretreatment such as alkali bath is required before pickling, resulting in complicated treatment process and poor surface quality after pickling. The composition and weight ratio of the pickling agent are: 30%-80% hydrochloric acid with a concentration of 30%, 17.2%-69.7% hydrofluoric acid with a concentration of 50% or 55%, and 0.3%-3.8% corrosion inhibitor. The corrosion inhibitor can be hexamethylene tetraammonium or rhodin or LK type corrosion inhibitor. The prominent feature of the direct pickling agent for chromium stainless steel is that it can directly remove the scale of chromium stainless steel without pretreatment such as alkali bath, which simplifies the treatment process. Experiments have proved that the pickling agent has excellent protection performance on the surface of chromium stainless steel, and the pickling surface is smooth and white, which is similar to that of austenitic stainless steel. It is suitable for pickling of chromium stainless steel wire, bar, profile, pipe, plate, wire, etc. and mechanical parts in the state of heat processing and heat treatment.