Bm04862 is a novel hemocyte-specific gene, which has been identified and cloned through the microarray data in silkworm, Bombyx mori. Initially, we successfully obtained the full-length cDNA sequence of Bm04862 via the rapid amplification of cDNA ends (RACE). The sequence consists of an open reading frame (ORF) with 819 bp, which could encode 273 amino acid residues. The bioinformatics analysis predicted that Bm04862 was a transmembrane protein. Furthermore, qRT-PCR analysis revealed that the expression of Bm04862 was specifically detected in hemocyte and reached a peak at L4M and PP2 stage. Bm04862 was overexpressed in Sf9 insect cells, and the cellular localization indicated that Bm04862 was specifically located in cytoplasm and nuclei membrane. Interestingly, the expression of Bm04862 increased dramatically after challenged with Escherichia coli for 24 hours, which predicted its potential role in the innate immune system. Overall, this study could provide the fundamental knowledge for further research.