The invention relates to a multimode support parallel multichannel fast frequency sweeping method and a multimode support parallel multichannel fast frequency sweeping system. The system consists of four parts including a broadband radio frequency part, a multimode medium frequency part, a baseband frequency sweep algorithm part and a software configuration module, wherein the broadband radio frequency part is mainly used for carrying out analog amplification, filtering, frequency mixing, analog-to-digital (A/D) conversion and the like on the received radio-frequency signals; the multimode medium frequency party is mainly used for carrying out down-conversion treatment on digital intermediate frequency signals, wherein digital frequency mixing is carried out on the signals before down-conversion; the baseband frequency sweep algorithm part mainly comprises a frequency point detection module and a power calculation module; the frequency point detection module is used for rapidly and accurately judging frequency points, and the power calculation module is used for determining a main base station frequency point and a neighbor cell site frequency point; the software configuration module is used for carrying out online configuration on radio frequency and intermediate frequency by an upper computer, so that broadband radio frequency and multimode medium frequency are realized, and multiple communication systems are compatible. The multimode support parallel multichannel fast frequency sweeping system is capable of realizing rapid frequency sweeping of multiple communication modes such as global system for mobile communication (GSM), code division multiple access (CDMA), wideband code division multiple access (WCDMA), line termination equipment (LTE) and the like; the system is high in flexibility, rapid in speed, wide in application scope and cost-saving.