Abstract: We propose a Form-based approach for reverse engineering of legacy relational database applications. The approach consists of three dependent steps: (1) Acquisition of both structure and instances of forms, (2) Extraction of static aspect of legacy database: through a combination of forms structures and data instances analysis, forms relational sub-schemas and their constraints are derived. These relational sub-schemas are mapped into object sub-schemas, which will be merged into global object schema that presents the whole underlying database. (3) Extraction of dynamic aspect of legacy application: through the results of static aspect extraction, form behavior relationships are extracted in order to construct both methods call graph of form and forms network.