Abstract: A recombinant adenovirus vector comprises eukaryotic cell promoter, operator, Kozak sequence, exogenous gene and PolyA signal sequence from 5? to 3? in the adenovirus vector backbone. Optionally, introns are inserted between the operator and Kozak sequence, and the exogenous gene is p53 gene. A recombinant adenovirus obtained by co-transfection of the adenovirus vector and adenovirus backbone is also included in the invention. Also disclosed are the preparation methods and uses of the recombinant adenovirus vector and the recombinant adenovirus, respectively. The present invention further discloses a pharmaceutical composition for treating cancers, which comprises the recombinant adenovirus.