Environment played a crucial role in the growth, development and survival of worms. In life history of tasar silkworm, the larvae were amenable to abiotic stress conditions which affected the morphological characters of the worms. In present investigation, vital environmental factors like temperature, and photoperiod were studied regularly to assess their impact on the life history of tasar silkworm, adult emergence, weight, length, width of larvae as well as cocoons. In addition, survivability rate, mortality rate and shell ratio were also studied. The grainage period consist of 5 groups of different temperature ranges- above 35 ℃ (gp1), 25 ℃ (gp2), 23 ℃ (gp3), 28 ℃ (gp4), below 10 ℃ (gp5) in order to study the best suitable temperature range for emergence and hatching. The results showed that temperature below 10 ℃ and above 35 ℃ hindered worm survival. The optimum temperature for normal growth of silkworm was found between 20-28 ℃ and the best suitable temperature range for maximum productivity was 23 ℃-28 ℃. Effect of photoperiod on larval stages was also studied which comprised of three groups: Group Ⅰ (13hours light : 11hours dark), Group Ⅱ (24 hours dark) and Group Ⅲ (24 hours light). Duration of life cycle, cocoon weight, quality of cocoons, shell weight and shell ratio in dark condition was significantly (p<0.05) better than larvae kept in normal and light conditions.