The invention discloses a method which is used for detecting and quantifying target material and based on nucleic acid aptamer and a solid-phase biosensor used for detecting, wherein, the method comprises the following steps: (1) capture probes are connected to the surface of magnetic particle, and the sequence of the capture probes comprises the nucleic acid aptamer sequence of the target material; (2) a sample to be tested is added for reaction; (3) signal probes and bridge molecules are hybridized to obtain double-stranded nucleic acids, and the signal probes are added into the reaction system obtained by step (2) through a double-stranded mode for reaction, the magnetic separation is then carried out to remove free signal probes; (4) the signal probes are separated from the surface of the magnetic particle by a nucleic acid denaturation way, and the fluorescent signals on the signal probes are detected. The method is suitable for detecting wide target materials comprising protein, organic micromolecule, metallic ions, and the like. The method not only has higher sensitivity, but also solves the nonspecific problem and has important meanings in bioinstrumentation, early diagnosis and treatment of disease.