The present invention discloses a reproductive recombination virus for treating tumor associated with EB virus and its building method. Some cis-acting element, which can only be specifically activated in dormant infection or infected cells of EB virus, is inserted into upstream region of early gene of said virus, so said virus can be only reproduced in dormant infection or infected cells of EB virus, not in normal cells, and can specifically kill the dormant infection or infected tumor cells. The tumors to be treated includes nasopharyngeal cancer, Burkitt lymphomatosis, gastric cancer, etc.