The invention provides a signal processing method and a signal processing device, comprising the following steps of: acquiring a first temperature signal, and determining a target wavelet basis and atarget number layer; performing wavelet decomposition on the first temperature signal based on the target wavelet base and the target layer number to obtain a target wavelet decomposition coefficient;performing wavelet reconstruction on the target wavelet decomposition coefficient to obtain a second temperature signal. According to the signal processing method and signal processing device, the error of the temperature signal measured by the embodiment of the invention is small, so that the accuracy of the measured temperature signal is high.