The invention discloses an analog-to-digital conversion system and an analog-to-digital conversion method. The system comprises an analog-to-digital converter to be compensated, a data transferring module and a digital pre-distortion anti-model module, wherein the analog-to-digital converter to be compensated is used for converting an acquired analog signal into a digital signal of a real number field; the data transferring module is used for transferring the digital signal from the real number field to a complex number field; and the digital pre-distortion anti-model module is used for compensating the digital signal in the complex number field according to the inverse process of the distortion of the analog-to-digital converter to be compensated to obtain compensation data. By the invention, the digital signal is compensated in the complex number field, so the problem of spectrum distortion caused by intermodulation distortion is solved, the capability of response of the system to the signal is improved, and the acquired analog digital is reflected more really.