Real-time and fast trapping and tagging of microfeatures, such as microparticles and cells, are of great significance for biomedical research. In this work, we propose a novel in situ digital projection lithography technology that integrates real-time, in situ generation of digital masks for particle processing and fluid control into conventional DMD-based projection lithography. With the help of image recognition technology, we rapidly resolve the information of the microparticle profile or channel location, combining the selection of existing masks of different shapes, thus enabling in situ generation of user-customized micro-trap arrays and microfilter arrays for particle trapping and tagging. The success in trapping and filtering single particles, particle arrays, and cells has indicated the promising prospects of this novel technology for broad applications in microfluidics, single-cell analysis, and early-stage disease diagnostics.