The present disclosure provides an isolated recombinant oncolytic adenovirus, a pharmaceutical composition, and uses thereof for drugs for treatment of tumors and/or cancers. The recombinant oncolytic adenovirus is a selectively replicating oncolytic adenovirus, and the genome of the recombinant oncolytic adenovirus is integrated with a coding sequence of exogenous shRNA capable of inhibiting PDL1 expression in tumor cells. The replication capability of the virus in normal primary cells is much lower than the replication capability of the virus in tumor cells. Moreover, the expressed shPDL1 can significantly reduce the level of PDL1 protein highly expressed in tumor cells. Thus, the oncolytic killing effect of the oncolytic virus and the anti-tumor immunostimulatory effect of immune cells produce a synergistic effect.