An integrated library automation system-SIOCL system is reported. Eight noteworthy problems on the design of ILAS are discussed in detail based on the experience from design of SIOCL system. They are the choice of the type of computer and applied software. the relationship between ILAS and network system, the retrieval efficiency of the system, the relations of ILAS with bibliographic retrieval of secondary literatures, the enhanced circulation control in ILAS, data structure and data sources in ILAS etc.