Double-stranded RNA (dsRNA) can induce sequence-specific inhibition of gene function, this phenomenon is termed RNA interference (RNAi). An effective RNAi method of silkworm (Bombyx mori) embryo by introduction of double-stranded RNA corresponding to the silkworm Bmwh3 gene into the preblastoderm eggs of wild-type has been established based on the previous research. The results showed that the RNAi was successful when injected Bmwh3 dsRNA into the preblastoderm eggs within 8h after laid of wide-type silkworm and the concentration of the Bmwh3 dsRNA must be high to 2.0 g/L. It can also induce the other w3 mutant phenotype——translucent larvae when injected Bmwh3dsRNA into the third day of developed eggs. A conclusion can be primarily drawn that the Bmwh3 is not only involved in the transport of the precursors of the ommochrome and pteridine pigments to the eye and egg，but also involved in the transport of the precursors of the pigments to the larvae skin.