Precisely assembled DNA nanostructures are promising candidates for the delivery of biomolecule-based therapeutics. Herein, we introduce a facile strategy for the construction of a branched DNA-based nanoplatform for codelivery of gene editing (sgRNA/Cas9, targeting DNA in the nucleus) and gene silencing (antisense, targeting mRNA in the cytoplasm) components for synergistic tumor therapy in vitro and in vivo. In our design, the branched DNA structure can efficiently load a sgRNA/Cas9/antisense complex targeting a tumor-associated gene, PLK1, through DNA self-assembly. With the incorporation of an active targeting aptamer and an endosomal escape peptide by host-guest interaction, the biocompatible DNA nanoplatform demonstrates efficient inhibition of tumor growth without apparent systemic toxicity. This multifunctional DNA nanocarrier provides a new strategy for the development of gene therapeutics.