Abstract: A sequencing method comprising: (i) combining a template nucleic acid having a first optical detection label at the end with a primer to obtain a first complex; (ii) imaging the first complex to obtain a first image; (iii) mixing the first complex, polymerase, and one or more of nucleotides with a optical detection label to obtain an extension product by polymerization reaction; (iv) imaging the extension product to obtain a second image; (v) removing the cleavable group of the nucleotides with the optical detection label from the extension product to obtain a second complex; (vi) repeating the above steps (ii) to (v) once or more times to determine the template nucleic acid sequence. The sequencing method can achieve single molecule sequencing by capturing template nucleic acids through primers.