Joint for pooling library building of multiple samples, kit and library building method

The invention discloses a linker for multi-sample pooling library establishment, a kit and a library establishment method, the linker comprises a linker positive chain and a linker negative chain, the sequence of the linker positive chain is as shown in SEQ ID NO.1, and the sequence of the linker negative chain is as shown in SEQ ID NO.2; and the joint positive chain and the joint negative chain form a double-chain joint after annealing. According to the scheme, two-stage tags are designed for the connectors, on the basis that the connector synthesis cost is effectively saved, the number of available connectors is greatly increased, enough connectors are provided for large-scale sample pooling sequencing, the problem that the number of connectors is insufficient frequently occurring during multi-sample pooling sequencing is effectively solved, the unequal-length connectors of the 4-8bp inner-layer tag sequence have the advantages that the number of the connectors is increased, and the number of the connectors