Method for breaking nucleic acid and adding adaptor by means of transposase, and reagent

Provided are a method for breaking a nucleic acid and adding an adaptor by means of a transposase, and a reagent. The method comprises the following steps: conducting random breaking of a nucleic acid by using a transposase-embedded complex, wherein the transposase-embedded complex comprises a transposase and a first adaptor comprising a transposase identification sequence, and two ends of the broken nucleic acid are separately connected to the first adaptor and are separately provided with a gap; by means of purification or chemical reagent treatment, eliminating the influence of the transposase in the system on a follow-up reaction; connecting to a second adaptor at the gap by using a ligase, wherein a sequence of the second adaptor is different from a sequence of the first adaptor; and conducting a PCR reaction by using primers targeted to and combined with the first adaptor and the second adaptor respectively, so as to obtain a product whose two ends are respectively connected to different adaptor sequences.