Abstract: The present invention provides an insect infection method for use in the production of a protein with a baculovirus expression vector in the insect, the method comprising the steps of: (g) providing a plurality of insect larvae or pupae; (h) providing a solution comprising a wild type baculovirus or a baculovirus expression vector having a desired gene encoding a protein; (i) stressing the insect larvae or pupae; (j) soaking the insect larvae or pupae in the solution for an appropriate time so that they are infected with the wild type baculovirus or the baculovirus expression vector; and (k) incubating the infected larvae or pupae for production of the protein; and (l) harvesting the protein. The method can treat a great quantity of larvae simultaneously, achieve batch infection of larvae or pupae, save manpower and effectively infect larvae or pupae at a high infection rate.