The invention, which belongs to the technical field of medical ultrasonic detection and treatment, provides a wearable medical ultrasonic therapeutic apparatus and an acoustic emission array positioning and acoustic beam focusing method. Using the apparatus and method provided by the invention, problems of difficulty existing fixation equipment installation and maintenance and limited focusing region can be solved. The method comprises the following steps: step one, designing a head-mounted device, a limb-mounted device, and a trunk-mounted device, calculating equipment attitude information, and storing the information in a table manner for convenient FPGA invoking; step two, selecting one device, installing the device, and adjusting an attitude device to prevent dead angle generation; step three, operating the device, collecting magnetic positioning device information on an array, calculating a spatial attitude of the array, and carrying out positioning to determine coverage of a therapeutic region by the device; step four, determining a therapeutic focusing center, looking up the table and carrying out calculation, adjusting the attitude position and an ultrasonic array emission time delay, and forming a focusing center; and step five, with a B type ultrasonic detection, feeding back the focusing position information in real time, carrying out closed-loop feedback adjustment, and correcting a focusing position attitude error.