The present invention provides a digital hologram recording system and a numerical reconstruction method for a hologram, which are used for capturing an image of an object and recording it as a holographic data. Said system comprises: signal light, formed after irradiating the object with a light source; an image detector, for recording interference fringes of the signal light; and a light pipe, arranged in a path of the signal light and located between the object and the image detector, wherein the light pipe has a reflection surface, and a part of the signal light enters the image detector after reflected by the reflection surface of the light pipe. The present invention can make the collected signal equivalent to several times of the pixel counts of the image detector, thereby able to break through the spatial bandwidth limitation and shortening the amount of time required to measure the hologram.