Abstract: Farmland shelterbelt has an important ecological effect on agroecosystem.A comparative analysis was conducted of soil organic carbon(SOC) and soil microbial biomass carbon(C_mic)in field with shelterbelt and fields under crop rotation in the hilly region of central Sichuan basin,to study effects of cypress shelterbelt on two parameters.Results show that SOC and C_mic contents in the farmlands(under rapeseed-maize rotation and monocropping of maize) with shelterbelt were significantly higher than that in the farmlands without shelterbelt,and declined with the increasing distance from the shelterbelt.However,in the fields without shelterbelt,the distribution of SOC and C_mic did not vary much.According to the multifactor variance analysis,shelterbelt had significant effects on both SOC and C_mic,while crop rotation had such effect only on soil C_mic in the shallow soil layer.The experiment showed that on the whole the cypress shelterbelt can improve SOC content in the farmland,but it does somewhat affect growth of the crop in its vicinity.It is,therefore,advisable to alter the composition or restructure the pure cypress shelterbelt.