The invention belongs to the field of signal processing, and specifically discloses a look-up-type three-redundancy signal processing method, which includes the following steps: (1) measuring the three-way redundant channel V x1 , V x2 or V x3 (2) Calculate the difference ΔV between two pairs of three redundant signals x12 , ΔV x23 , ΔV x13 ; (3) Query the triple redundant signal lookup table: (3.1) Judgment ΔV x12 , ΔV x23 , ΔV x13 and the relationship between the fault judgment threshold value Δ, and check the table above: when ΔV x12 , ΔV x23 , ΔV x13 When it is less than or equal to Δ, the global variable K=0, indicating that the three channels are normal, and one channel is selected as the current three-redundant signal processing result; (3.2) When the global variable K is not equal to 0, continue to judge ΔV x12 , ΔV x23 , ΔV x13 The relationship with Δ, and look up the above table to get the result of triple redundant signal processing. This method can minimize the pulsation of triple redundant signal processing results.