The present invention discloses a rapid evaluation method for quality of lignin-pyrolyzed bio-oil and an application thereof, and particularly relates to a rapid evaluation method for quality of lignin-pyrolyzed bio-oil based on radical detection and an application thereof. The method can be used to evaluate the quality of lignin-pyrolyzed bio-oil by detecting the spin concentration of radicals in lignin char obtained by lignin pyrolysis, thus avoiding the complex processes involved in the evaluation for the quality of conventional pyrolyzed bio-oils such as, extraction, separation and detection and reducing the detection costs substantially. The detection method of the present invention is simple and easy to operate, thus achieving the rapid evaluation for the quality of lignin-pyrolyzed bio-oil. Moreover, the detection method of the present invention is non-contact detection without destructive samples, which is applicable to the rapid detection on the quality of lignin-pyrolyzed bio-oil in the field of industry and scientific research. The present invention further broadens the application fields of radical detection and contributes to the development of radical detection technology in the field of pyrolysis, and provides a reliable method for the detection of lignin-pyrolyzed bio-oil, which has good application prospect.