The invention relates to a detachable combined anti-misoperation locking box suitable for a power transformation protection screen. The detachable combined anti-misoperation locking box comprises a box body and warning plates. The two sides of the box body are provided with positioning plates which are inwardly and vertically recessed in a mirror symmetry way. Positioning magnets are embedded in the positioning plates via embedding holes. Height-limiting square frames are manufactured in the box body between the positioning plates in a uniform distribution and spacing way. Multiple secondary element locking sleeves are manufactured on the box body in each height-limiting square frame. One warning plate is installed at the external surface of each corresponding height-limiting square frame in a magnetic absorption way. A connected buckling box type structure is adopted by the locking box, and secondary elements in each segment of protection screen can be positioned in the insulating box. Meanwhile, the locking sleeve locking the secondary element is manufactured in the insulating box corresponding to each secondary element, and all the secondary elements can be synchronously positioned so that change of the secondary elements caused by any misoperation of operators can be effectively avoided, and calibration safety of a transformer substation can be greatly guaranteed.