A CRISPR-Cas12a-based strategy is developed for sensitive microRNA sensing, in which hyperbranched rolling circle amplification and transcription are integrated for the activation of the trans-cleavage ability of Cas12a. The integrated triplex signal amplification endows the strategy with a low background and high sensitivity. This design expands the scope of the CRISPR-Cas-based sensing toolbox and shows great potential in biological and biomedical studies.