The disclosure discloses methods for determining fitting model for a signal, reconstructing a signal and devices thereof. The determination method may comprise the following steps: segmenting a sampled signal based on collected characteristic information of the signal to obtain a plurality of signal segments; fitting sampling points in the plurality of signal segments using a plurality of fitting models; acquiring fitted values for a parameter of interest in each signal segment based on fitting results; comparing each of the fitted values for the parameter of interest under each of the fitting models with an acquired measurement value for the parameter of interest, and determining a final fitting model for reconstructing the signal among the plurality of the fitting models based on comparison results. In the technical solution provided in the disclosure, the accuracy of the signal reconstruction result and precision of the signal reconstruction may be improved.