African swine fever (ASF) is an infectious disease caused by African swine fever virus (ASFV) with clinical symptoms of high fever,hemorrhages and high mortality rate,posing a threat to the global swine industry and food security.Quarantine and control of ASFV is crucial for preventing swine industry from ASFV infection.In this study,a recombinase poly-merase amplification (RPA)-CRISPR-based nucleic acid detection method was developed for diagnosing ASF.As a highly sensitive method,RPA-CRISPR can detect even a single copy of ASFV plasmid and genomic DNA by determining fluorescence signal induced by collateral cleavage of CRISPR-lwCasl3a (previously known as C2c2) through quantitative real-time PCR (qPCR) and has the same or even higher sensitivity than the traditional qPCR method.A lateral flow strip was developed and used in combination with RPA-CRISPR for ASFV detection with the same level of sensitivity of TaqMan qPCR.Likewise,RPA-CRISPR is capable of distinguishing ASFV genomic DNA from viral DNA/RNA of other porcine viruses without any cross-reactivity.This diagnostic method is also available for diagnosing ASFV clinical DNA samples with coincidence rate of 100％ for both ASFV positive and negative samples.RPA-CRISPR has great potential for clinical quarantine of ASFV in swine industry and food security.