A cross-platform database access method comprises the steps that UQL is initialized; UQL statements are written; the UQL statements are preprocessed; whether grammar judgment is conducted is determined; formalization packaging is conducted on corresponding grammars, and XML expressions are generated; the XML expressions are analyzed to obtain corresponding parameters; according to the obtained parameters, target database types of the UQL statements and access types of the UQL statements are extracted, and parameter filling and executing are conducted on a selected corresponding basis module; formalization packaging is conducted on an executed result, and return is conducted. According to the method, the inner service method is no longer a target specific method but is a simple procedure in which a universal analysis executing module omits a service direct calling method in past at an iOS client, and the purpose of data access is achieved through data access statements.