The invention discloses a cold belt rolling mill panel thickness limited frequency domain feedforward control compensation method based on wave function, including the following steps: step one, a measuring device is utilized to measure process information online; step two, calculating is carried out by Psi(p.deltaL, t), wherein p is equal to -N, -N+1,..., N; step three, wavelet decomposition level is determined; step four, a wavelet decomposition method is adopted to decompose a Psi(p.deltaL, td) sequence, thus obtaining low frequency components and detailed components of each level; step five, Psi(p.deltaL, td) is made to be equal to GML(p.deltaL, td)-GMH(p.deltaL, td); step six, setting of cleaning between rolls is adjusted by the obtained Psi(0, td) by a feedforward compensator. The invention adopts the wavelet filtering method to reduce overlap of action range of feedforward and feedback frequency domains in the panel thickness control system, realizes orthogonalization of feedforward and feedback control actions to the utmost extent, reasonably reduces the action range of the feedforward frequency domain, is beneficial to optimization of parameters of the feedforward compensation system, improves the matching efficiency of two basic control manners of feedforward and feedback in the panel thickness control system, and finally can effectively improve panel thickness control precision.