Students' knowledge on system for open and distance learning (ODL) is important since the information will be usefull in improving students' services. This article discusses students' understanding on ODL system and factors that affect it. The sample were 380 students from UPBJJ-UT Banda Aceh. Data collection was carried out from May to October 2011. Correlation test of Rank Spearman was used to analyze the data. The result showed that (1) students' knowledge on distance learning system was low (2) factors which influences students knowledge on ODL system were ability in using internet, study group and information access.