In order to study rice husk pyrolysis process thermochemical conversion of energy and exergy relations. In this paper，a downdraft fixed bed rice husk pyrolysis system was designed and established. The designscheme of the experimental system and the working principle of pyrolysis reaction system was introduced. The yield of each rice husk pyrolysis reaction product was measured by experiment. The energy and exergy of rice huskpyrolysis products were analyzed. The relationships of energy and exergy for pyrolysis products at different pyrolysis temperatures were obtained. The results indicate energy value and exergy value contributions of the components in the pyrolysis gas from 500℃ to 700℃ are CH 4 ＞ CO ＞ H 2 ＞ CO 2 . At 700℃ and 800℃ the rank turns into CO ＞ CH 4 ＞ H 2 ＞ CO 2 ; The work will provide reference for the development of economical and efficient pyrolysis reactor.