The invention relates to the technical field of vehicle-mounted radars, in particular to a radar antenna butt joint interlocking device and method; the interlocking device comprises an opening and closing mechanism, a fixed hook, a fixed column and a blocking antenna, wherein the opening and closing mechanism and the fixed hook are fixedly connected to the two sides of the blocking antenna respectively; the fixed hook can be clamped on the opening and closing mechanism, and the fixed column can push the opening and closing mechanism to be opened and closed; installation and splitting of the plurality of blocking antennas can be completed through pushing and shrinking of a power source; rapid locking of the plurality of blocking antennas can be realized through two opening and closing tongsand hook claws which are connected on the blocking antennas, and no power assistance and manual intervention are needed, so that the stability and the efficiency of the self-locking connection can beimproved through the two opening and closing tongs and the hook claws which are connected on the blocking antenna.