RNAi is a recently developed method to block the activity of cellular genes by artificially providing sense and anti-sense RNA corresponding to a target gene. By inducing rapid degradation of the corresponding endogenous mRNA and blocking new mRNA synthesis, RNAi leads to post-transcriptional gene silencing. Now this phenomenon has been claimed to exist in C. elegans, Drosophila, buds, fungi and plants and is being used to study the functions of some special genes or the known genes at specific time point. It is extremely useful for those genes or organisms that their mutants are not easily obtained. The Drosophila heart related genes, tinman and wingless, have been shown to play an important role in coordinating the early formation of heart progenitor cells and precursors, yet the late function is still unexplored. In this experiment, we took the advantage of RNAi technique, microinjected tinman and wingless dsRNA into the early embryos in Drosophila respectively and got these two genes' RNAi phenotypes, which were very similar to that of their mutant, showing heart tube defects or no heart precursors formation. tinman dsRNA even caused visceral mesoderm defects and the somatic muscles disruption, yet wingless dsRNA only affected heart precursors and had no effect on visceral mesoderm and somatic muscles, indication that the heart-related genes dsRNA interference worked effectively and exclusively in Drosophila.