The invention provides a system for estimating a carrier frequency deviation, comprising the following modules: a correlator module, a peak value search engine, an averaging device module, a phase angle difference calculator module and a carrier frequency deviation calculator module, wherein the correlator module is used for carrying out correlation calculation on a baseband signal and a locally-generated PN (Pseudo-Noise) sequence; the peak value search engine is used for carrying out peak value searching after receiving a parallel correlated value output by the correlator module, further determining a starting position of a PN section in the input baseband signal and feeding the position information back to the correlator module; the averaging device module is used for averaging results of the multiple times of correlated calculation of front and back sections, which are output by a correlator; the phase angle difference calculator module is used for calculating a phase angle difference of the correlated calculation and outputting the result; and the carrier frequency deviation calculator module is used for calculating an estimation value of the carrier frequency deviation and taking the estimation value of the carrier frequency deviation as an estimation value of PN rough estimation. The system has the beneficial effects that the problem that PN rough capturing is inaccurate when stronger multi-path interference exists can be effectively solved, and the robustness of the system under an actual wireless transmission channel can be improved.