Aiming at the low utilization of storage space in traditional single-sparse storage model and the problem of more connections in reconstructing the logical relationship of tenants in the block table storage model, the combination of sparse tables and block table storage model is put forward. In the storage model, the attributes in the logic tables provided by the SaaS providers and the attributes in the custom logical tables are mapped into the corresponding sparse tables and the custom attributes of a part of the tenant common data type are stored in the block table, so as to avoid the problem of data migration caused by the number of extended columns exceeding the number of sparse tables. Finally, the query conversion and query efficiency are optimized through the query rewriter. The experimental results show that the storage model improves storage space utilization and query efficiency compared with the traditional sparse table storage model.