The invention discloses a multichannel fusion detection method for distance extension targets under partially uniform environment, and belongs to the field of radar signal processing. According to themethod, a partially uniform multichannel auto-regression signal model is established for the condition of globally uniform auxiliary data missing caused by abnormal value conditions such as clutter edge and the like, so that local uniformity of clutter spaces, time low-order relevancy and multichannel information obtaining ability are sufficiently fused, the utilization rate of clutter prior information is effectively improved and a data model foundation is laid for auxiliary data demand of self-adaptive distance extension target detection; the multichannel fusion detection method for distance extension targets under partially uniform environment is established on the basis of a Rao test criterion, so that the auxiliary data demand is greatly reduced while the characteristic of constant-false alarm rate is ensured; and being compared with the common generalized likelihood ratio criterion method, the method is capable of simplifying the parameter estimation process while remaining thedetection performance unchanged, so that the detector construction efficiency is improved and the method is strong in engineering applicability and has popularization and application values.