The influence of temperature changes and period of incubation of silk worm eggs lines was found in 10˚, 14˚, 18˚, 26˚, 34˚, and 38˚C by exposing the fifth and the fourth larvae. The minimum level of fecundity that is 248 female eggs and the period of incubation of eggs reduced at a very fast rate 21. 67 days at 10 degree Celsius while the maximum fecundity rate 385 per female and the period of incubation were 9. 47 days at 26 degree Celsius. Above 26 degree both the fecundity and the incubation decreased considerably. The best temperature that is needed for rearing silkworm lines for cocoons production obtaining highest number of eggs with short period of incubation with increased rate of fertility is at 26 degree Celsius and 12 hours day light in one day that can be used in seed cocoon for hybridization and production. Investigations have shown that variation in temperature and humidity during the rearing of larvae resulted in low fecundity and high incidence of eggs that are not yet fertilized. The study has shown that incubation period, fecundity and fertility can be increased by avoiding temperature and levels of humidity.