Clustered regularly interspaced short palindromic repeats and its associated protein (CRISPR/Cas) is a powerful gene editing tool. Owing to the unique advantages, including high recognition specificity and efficient signal amplification ability, CRISPR/Cas has brought a next-generation biosensing technology. Our group developed a series of CRISPR/Cas mediated highly sensitive and specific nucleic acids (NAs) detection platforms, including (i) a CRISPR/Cas13a powered portable electrochemiluminescence (ECL) chip, (ii) a CRISPR/Cas-based visual detection system, (iii) a cascade CRISPR/cas (casCRISPR) signal amplification system without resorting to target amplification, and (iv) a universal ECL probe that can be compatible with automated and high-throughput ECL immunoassay analyzers. All these methods showed fM-level sensitivity and single nucleotide resolution, and can be used to detect microRNA, pathogenic bacteria gene or oncogene mutation. In these studies, we explored the trans-cleavage ability of Cas13a on ribonucleotide-bearing DNA oligo, eliminated the unavailability of the trans-cleavage substrate for subsequent polymerization reaction, and could provide heuristic ideas for CRISPR/cas based biosensing. With the further development of technology, CRISPR/Cas will play a broader role in the field of molecular diagnostics.