An encoding method, an encoder, and a decoder for dynamic power consumption control are provided. The encoder includes a control unit, an initial encoding unit, and L incremental encoding units. The control unit is configured to enable only the initial encoding unit in an RS (N0, K) operating mode to perform encoding or enable only the initial encoding unit and first j incremental encoding units in the L incremental encoding units in an RS (Nj, K) operating mode to perform encoding. The initial encoding unit is configured to perform RS FEC encoding on m(x) to obtain a quotient D0(x) and a remainder R0(x) of xN0−Km(x) relative to g0(x). An (h+1)th incremental encoding unit is configured to obtain, according to a quotient Dh(x) and a remainder Rh(x), a quotient Dh+1(x) and a remainder Rh+1(x) of xNh+1−Km(x) relative to gh+1(x).