As aC RISPR-Cas system (clustered regularly interspaced short palindromic repeats and CRISPR associated proteins), Cas14a1 can cis/trans cleave single-stranded DNA (ssDNA). Here,w ed escribe an unreported capacity of Cas14a1:R NA can trigger the trans ssDNAc leavage.T his Cas14a1-based RNA-activated detection platform (Amplification, Transcription, Cas14a1-based RNA-activated trans ssDNAc leavage,A TCas-RNA) has an outstanding specificity for the detection of target RNAs with point mutation resolution, which is better than that of the Cas14a1-based ssDNAactivation. Using ATCas-RNAv ia af luorophore quencherlabeled ssDNAr eporter (FQ), we were able to detect 1aM pathogenic nucleic acid within 1h,and achieve 100 %accuracy with 25 milk samples.This platform can serve as anew tool for high-efficiency nucleic acid diagnostics.Importantly,this work can expand our understanding of Cas14a1 and inspire further mechanisms and applications of Class-2 Cas systems.