In forming relation data model by converting directly from the E-R conceptual data model of a spatial attribute database,some data redundancy which may result in unexpected problems generally comes into being.For controlling the data redundancy,the relation data model usually is decomposed into normalized third normal form(3NF) based on relation normalization theory,but the manual decomposition takes a lot of time and labor.In the paper,a new general algorithm which can automatically decompose relation data model into third normal form(3NF) for the design and optimization of spatial attribute database is proposed.The new algorithm is also applicable to general relational database.