Abstract: Objective To study the value of MSCT 3-dimensional imaging in reconstruction of middle ear and in diagnosis of chronic otimastoiditis. Methods Sixty-eight patients with chronic otimastoiditis underwent 128-layer spiral CT scanning and transparent volume reconstruction (VR) and multiple plane reconstruction (MPR) to observe the morphology of ear ossicles in normal control group and the bone structure destruction of middle ear and mastoid in lesion group. The outcomes in the two groups were compared after operation. Results MSCT 3-dimensional imaging could show the functions of malleus, incus and hammer anvil joints after VR and MPR, and the partial functions of stapes and stirrup anvil joints after MPR in normal control group. The diagnosis of middle ear and mastoid bone destruction established by MSCT 3-dimensional imaging was basically consistent with that established by surgical pathology in 76 ears of lesion group. Conclusion MSCT 3-dimensional imaging can clearly show the fne structure of middle ear and accurately diagnose the middle ear and mastoid bone destruction, but cannot clearly show the functions of stapes, stirrup anvil joints and their bone destruction.