The present invention provides a nucleic acid vector referred to as pVec constructed through molecular biotechnologies. pVec contains CMV enhancer/promoter, T7 promoter, 5′；UTR, MCS, 3′；UTR, poly A (120A)-TTATT, BGH poly (A) signal, kanamycin resistance gene and pUC origin, etc. So pVec can be used as a vector for both DNA vaccines or therapeutic drugs and mRNA vaccines or mRNA therapeutic drugs. The 5′；UTR, 3′；UTR and poly A (120A)-TTATT of pVec can be added to the 5′； and 3′； ends of the in vitro transcribed mRNA respectively and further stabilize the transcribed mRNA. The present invention also provides the constructed pVec-GM-CSF, pVec-hIL-12 and pVAX1-hIL-12, which are used for evaluating the benefits of pVec.
