Abstract: The traditional way to foster silkworm had many defects, such as inconvenient to use, easily lead to misoperation and probable to hazard silkworm by poison gas produced by coal stove. In the light of this situation, it was introduced to design a new temperature and humidity control system for common foster room based on LPC1111.The system used semiconductor refrigeration piece as a new cool and heat source which combined with moisture absorption characteristic of acrylic resin to realize simple dehumidification, and closed-loop control system by using temperature and humidity sensors was built. The design of temperature and humidity control and its specific hardware circuit and software process were introduced in the article. Test results showed that the maximum deviation of temperature was one degree Celsius, and the maximum deviation of humidity was six percent. Consequently, the live environmental requirements for young silkworm could be met by setting the temperature and humidity reasonably.