An application interoperation method includes: maintaining a handler table including data type information, function information and calling information associated with each application installed in a portable device; receiving input information on a menu key of the portable device, from a user, while a first application is active; extracting, in response to the receipt of the input information, at least one function information associated with data type information, which is being processed or requested by the first application, from the handler table; dynamically generating a menu including the extracted function information to provide the user with the generated menu; receiving selection information on particular function information among the provided menu, from the user; and identifying calling information associated with the selected particular function information by referring to the handler table and executing a second application on the basis of the identified calling information.