The invention provides a background inhibiting method applied to a deep space X-ray detection spectrometer, and relates to anti-radiation technology of deep space detection. The method comprises the following steps: (A) using a collimator with distribution of an intensity magnetic field to reduce radiation background; (B) using an amplitude analysis anti-coincidence method to alleviate the noise pollution and reduce the counting rate; and (C) applying multi-channel isolation technology to close a high-noise signal channel and reduce the total noise of the spectrometer. The method comprehensively utilizes the collimator with the magnetic field to shield background particles and utilizes the amplitude analysis anti-coincidence and the multi-channel isolation technology to inhibit the background of the spectrometer.