The invention relates to the microwave performance testing field of the circuit board and provides a method and apparatus for realizing self-calibration of the microwave performance of a multi-layer circuit board, thereby solving problems in the prior art. Using the method and apparatus provided by the invention, the joint losses, assembling influence, and circuit mismatching influence due to an external testing clamp can be eliminated and thus accurate circuit board testing data can be obtained, thereby serving for simulation parameter correction and simulation precision improvement. According to the method, on the basis of a channel A1, n-1 equations of A2 to An are designed; when the total insertion loss Ki is obtained by a channel Ai, at least one of coefficients of four parameters (B, T, R, and D) changes by being compared with coefficients of corresponding four parameters in the total insertion loss K1 of the channel A1, wherein the i of the Ai is equal to 2 to n and the i of the Ki is equal to 2 to n; and the coefficients of the four parameters (B, T, R, and D) have changed at least one time by corresponding the coefficients of the A1.