Abstract: Disclosed in the present invention is a method for constructing a sequencing library. The method comprises: (1) performing reverse transcription treatment on a mRNA to obtain a reverse transcription product without the need of adding a template switch oligo, the 3? end of the mRNA containing a poly-A sequence, the mRNA being connected to a chip, the chip being connected to a probe containing a poly-T sequence, and the connection being realized by means of the complementary pairing of the Poly-A sequence at the 3? end of the mRNA and the poly-T sequence on the chip; and (2) performing fragmentation on the reverse transcription product and ligating a first adapter to same so as to obtain a fragmentated and adapter-ligated product, the fragmentated and adapter-ligated product being connected to the chip; and (3) releasing the fragmentated and adapter-ligated product from the chip, so as to obtain a sequencing library.