A signal processing method and device are disclosed. The method include: receiving a first signal; processing the first signal to obtain a squared complex envelope of the first signal; obtaining a second signal by processing the squared complex envelope of the first signal using a first filter, where a cutoff frequency of the first filter is determined according to an average-to-peak power ratio of a squared complex envelope spectrum of a third signal, the third signal is obtained by processing the first signal using a second filter, and a cutoff frequency of the second filter is determined according to a bandwidth occupied by the first signal; determining a squared complex envelope spectrum of the second signal; and determining a symbol rate corresponding to the first signal according to the squared complex envelope spectrum of the second signal. As such, the symbol rate of the signal can be determined accurately.