The invention provides a three-dimensional wide-beam small-region rapid cavitating and imaging method of an ultrasonic two-dimensional planar array. According to the three-dimensional wide-beam small-region rapid cavitating and imaging method, a linear scanning way adopted by the conventional ultrasonic imaging technology is abandoned, but a single-time three-dimensional wide-beam imaging method is used, so that problems, existing in imaging of transient physical information, of time asynchrony and motion blur can be solved, and the imaging frame rate can reach 5kHz; furthermore, in allusion to the problem that single-transmission three-dimensional wide-beam rapid imaging signal-to-noise ratio is low, a multi-angle continuous three-dimensional wide beam is used for composite imaging, 5 spatial continuous different-angle three-dimensional wide beam transmissions, as an example, are used for cavitating composite imaging, and the imaging frame rate can still reach 1kHz.