Abstract: In order to effectively prevent the violations of provision and discipline in tobacco leaf purchasing,an internal supervision system was designed. A basic data set was built from the existing tobacco information systems, the data about purchasing time, tobacco weighing, invoice, inventory and shipping were analyzed, from abnormal data to find any possible misconduct in leaf purchases and achieved the aim of internal supervision. The system was applied in 442 purchase points in Zunyi City of Guizhou Province, the practical application results showed that the system featured stable running, timely data inquiring and effective monitoring, the violations occurred at 29 purchase points were disclosed timely,and the interests of tobacco enterprises and tobacco growers were protected.