Polycomb repressive complex 1 (PRC1) plays important roles in regulating developmental genes and maintaining the embryonic stem cells (ESCs) identity. PRC1 complex has many variants, however, it is not known how and where these variants are recruited to their lineage-specific genes. Here, we show that the transcription factor Kruppel-like factor 2 (Klf2) recruits Ring1b which is PRC1 enzymatic subunit and interacts directly in ESCs. Klf2 and Ring1b repress endoderm relating genes and downregulation of Klf2 and Ring1b causes endoderm differentiation of mouse ESCs. Thus, our study reveals that pluripotency has highly delicative repression mechanism controlled by recruitment of PRC1 complex through Klf2, and also demonstrates a important function of Klf2 in endoderm specific gene expression.