The utility model relates to an interlocking IO unification engine case of station interlock device, including interlocking operation layer and IO control layer, wherein, the unification engine case and bag contain two mother boards, and in the 6U machine cage that two mother board layerings were placed at a sixteen bit, two mother boards are little CPU mother board and little IO mother board respectively, and nine integrated circuit boards and six integrated circuit boards are placed respectively to two mother boards, through placing these two mother board layerings in 16 a 6U machine cage, realize the function that interlocking operation and IO controlled, and then the realization are with two, the interlocking rack unites two into one, realizes probably doing like this and saving the cost for the company for designing the configuration of minimum station, brings bigger economic benefits, saves space for the use at scene, brings the facility of installation and maintenance, more is favorable to practical application.