PURPOSE: A promoter of silkworm embryonic stage-specific expression gene and an active region of the gene are provided to early determine transformation. CONSTITUTION: A silkworm embryonic stage-specific expression promoter is isolated from a silkworm and is denoted by sequence number 1. The promoter is denoted by sequence number 2 and is formed by deleting 268bp at sequence number 1. A maximum promoter active region of a silkworm embryonic stage-specific expression gene contains the promoter. A method for preparing the promoter comprises: a step of screening early embryo gene(EEG) through isolation of genetic resources with respect to time using Bombyx mori eggs and acquiring cDNA clone; a step of analyzing the characteristic and structure of total base sequence and predicted promoter region with respect to the clone of EEG-704 cDNA gene; a step of preparing deletion mutant constructs of 11 kinds of genes with respect to the promoter of EEG704 gene; a step of transducing each deletion mutant construct to pGL