The invention discloses an encoding method of a channel error correcting code BCH code and an RS code, belonging to the digital communication field, which comprises calculating an adjoint polynomial S(x) through a received code R(x), solving the Berlekamp key equation through the Euclid algorithm to obtain an error location polynomial sigma (x), and correctly encoding if the constant term sigma 0 in the error location polynomial sigma (x) is zero, or calculating the error locations and the relative error values through the Chien search if the constant term sigma 0 in the error location polynomial sigma (x) is not equal to 0, and being able to correctly encode if the number of searched error locations is equal to the largest error correcting capability thereof, or sending a warning indication signal whose error number of receiving signals exceeds the largest error correcting capability, and outputting original receiving codes. The encoding method avoids the condition that the more errors are corrected, the more errors existing when the receiving code error number exceeds the largest error correcting capability of the channel error correcting code, thereby reducing the error code rate of the whole communication system.