The invention is applicable to the technical field of optical three-dimensional digital imaging, and provides a three-dimensional digital imaging method and device for a folded phase based on phase mapping. The three-dimensional digital imaging method comprises the steps of acquiring an image containing information of a measured object, and calculating a folded phase value of each pixel point on imaging planes of two imaging devices according to the image; calculating coordinates of n candidate space three-dimensional points corresponding to each pixel point via phase mapping by using the folded phase value of each pixel point on the imaging plane of the first imaging device and preset first calibration data; re-projecting the n candidate space three-dimensional points to the imaging plane of the second imaging device to obtain n candidate projection points, and interpolating folded phase values of the candidate projection points; and screening out correct space three-dimensional points from the candidate space three-dimensional points by taking the folded phase value of each pixel point on the imaging plane of the first imaging device and the folded phase values of the n candidate projection points corresponding to the pixel point as a basis so as to realize three-dimensional digital reconstruction. The three-dimensional reconstruction time is shortened according to the method provided by the invention.