The present application provides a vector for trapping an unknown gene of Drosophila melanogaster, which is a recombinant plasmid comprising the following nucleotide sequences in this order: an artificial consensus splicing acceptor site; a synthetic "stop/start" sequence; a reporter gene; a drug resistance gene; a gene responsible for a detectable phenotype of the Drosophila melanogaster; and a synthetic splicing donor site. The present application also provide a method for trapping an unknown gene of Drosophila melanogaster by using the vector.