The invention relates to an ultrasonic inspection device for the weld joints of pressure vessel connection tubes. The ultrasonic inspection device is characterized by comprising a guide rail assembly, a circumferential movement assembly, an axial drive assembly, a probe assembly, a press foot assembly and a circumferential drive assembly, wherein the circumferential movement assembly is embedded in the guide rail assembly and slides along an annular guide rail structure; the circumferential drive assembly is matched with the circumferential movement assembly; the axial drive assembly is connected with the circumferential movement assembly; a plurality of press foot seats are distributed along the circumferential direction of the guide rail assembly, and are fixed on the end surface of one side opposite to the open side of a guide tail groove of the guide tail assembly; rotation nuts are installed on the press foot seats and are connected to one end of a telescopic screw in a sleeving manner, and the other end of the telescopic screw is fixed together with a press block. According to the ultrasonic inspection device disclosed by the invention, inner surface inspection of large-dimension connection tubes/pipelines and outer surface inspection of small-dimension connection tubes/pipelines can be realized; the inner/outer wall diameter ranges of the connection tubes/pipelines which can be inspected by the inspection device are expanded; the installation and detachment convenience and speed of the probe assembly are remarkably improved.