An apparatus for downhole multi-dimensional imaging includes an acquisition unit configured to acquire a formation resistivity signal, an ultrasonic echo signal and an orientation signal regularly; a sector calculation unit configured to calculate, based on said orientation signal, a sector where a currently acquired signal is from; and a multi-dimensional imaging unit, configured to calculate, based on the signals acquired by the acquisition unit, data of resistivity, distance from a drilling tool to a borehole wall and ultrasonic echo amplitude, and distribute said data into all sectors for feature recognition and extraction, thus obtaining key features characterizing a current formation being drilled, said key features being transmitted to ground for guiding drilling process. The structural complexity and the length of the downhole imaging measurement instrument can be reduced, and feature recognition can be directly performed on the imaging data underground.