In situ target biomolecule analysis is of great significance for real-time monitoring and regulation of endogenous biomarkers and elementary biomole-cules in vivo.Gratifyingly,the rapid evolution of structural DNA nanotechnology during past decades has established an appealing toolbox for biological analysis and medical detection.The modulated self-assembly and underlying canonical Watson-Crick base-pairing rules provide possibilities for accu-rate controlling of the topologies and functions of obtained nanomaterials.The probes composed of diverse DNA nanostructures and DNA-nanoparticle complexes can create a confined space,which increases target accessibility and improves probe stability,sensitivity and specificity.In this minireview,we retrospect the research progress of in-situ biomolecular analysis based on DNA nanostructures for intracellular and in vivo biosen-sors in confined space.The characteristics of distinct DNA nanomaterials are first introduced,and then the fundamentals of biosensing process of de-signed DNA nanostructures are emphasized.Moreover,we elucidate our perspective over the challenges of this field and discuss the potential direc-tions of this kind of application-oriented fabrication technique.