The topical application of phytojuvenoid on Bombyx mori larvae has been proved to be of biotechnological significance in the sericulture industry. Total RNA content in the silk gland of larvae at the initial and final stage of spinning significantly influenced due to variation in the phytojuvenoid concentration and number of larval treatment. The total RNA content in the silk gland increased with the increasing number of larval treatment up to triple treatment of larvae in 10, 20 and 30% phytojuvenoid concentration which reached to the maximum level of 1.38 ±0.05 µg/mg in initial and 1.08±0.09 µg/mg in the final stage of spinning. The phytojuvenoid influences the level of protein in the larvae and caused some beneficial effect on the life pattern of silkworm and may also be helpful to device improvement in the rearing of Bombyx mori on industrial scale to boost up the production of silk.