The invention provides a three-dimensional reconstruction method, a three-dimensional reconstruction system, a mobile terminal and a storage device. The three-dimensional reconstruction method comprises the steps of acquiring the point cloud data (i.e., global point cloud data) of the first frame of three-dimensional measurement data, selecting a local area with an overlapped area in an area corresponding to the global point cloud data for measurement; acquiring and registering the local point cloud data, updating the global point cloud data, repeating the process until the measurement of allsurface areas is completed, and finally carrying out the global optimization processing on the updated global point cloud data after measurement is completed to obtain a point cloud model. According to the present invention, three-dimensional reconstruction is carried out through a method of breaking up the whole into parts, so that the high-density and high-precision measurement data can be obtained, and the method has more advantages especially for three-dimensional measurement of large-size objects.