The invention relates to a conditionally replicating oncolytic adenoviral vector used for expressing two exogenous genes and modified by
small peptide. Specifically, base 1083bp is deleted in the section of 2245bp-3327bp of human adenovirus type 5
genome, and an expression element expressing a first exogenous
gene is inserted into the section of 2245bp-3327bp of human adenovirus type 5
genome. And at 32679bp of adenovirus type 5
genome, i.e. at the position of
fibrin HI loop, a code containing a
small peptide is inserted. A second exogenous
gene of dual expression and an eGFP expression element are inserted into the section of 32787bp-32788bp of human adenovirus type 5 genome. The construction method of the vector includes the steps of: constructing a shuttle missed by pAd5E1B 55kd, constructing a shuttle of the first exogenous
gene pHE1B55D-, constructing an adenoviral vector backbone of the first exogenous gene pHE1B55D- / SwaI, constructing a shuttle of the
small peptide sequence pshuttle Ad5-E4-
fiber-, constructing a shuttle expressing eGFP and the second exogenous gene, and preparing the conditionally replicating oncolytic adenoviral vector used for expressing two exogenous genes and modified by small
peptide. The invention also provides the application of the adenoviral vector provided in the invention in preparing medicaments for treating tumours.