The invention provides simultaneous, rapid and continuous detection of multiple proteins, nucleic acids or pathogens by using a nanometer probe, paramagnetic micro-nano-particles and a microfluidic chip. According to the present invention, a monoclonal antibody or complementary nucleic acid sequence modified nanometer probe and antibody or nucleic acid modified magnetic micro-nano particle are used as detection reagents, a multi-channel microfluidic chip is used as a detection reaction cell, the antibody or nucleic acid modified magnetic micro-nano particle are immobilized on the bottom portion of the reaction cell by using a magnetic field to form a rewritable detection substrate, and an ultraviolet visible spectrophotometer, a fluorescence detector or an electrochemical detector is used as a signal acquisition device, such that the simultaneous and rapid detection of multiple proteins, nucleic acids or pathogens can be achieved; and based on the rewritability of the nanometer immune substrate and the anti-adhesion property of the chip material, the detector can achieve the continuous testing of different samples so as to substantially improve the detection automation and the sample treatment ability, and has wide application values in the fields of disease diagnosis, infectious disease monitoring, food hygiene and safety monitoring, and the like.