Screen display ratio adjusting aparatus and method

A screen display ratio adjusting apparatus includes a handheld device and a display device. The handheld device includes an application module which obtains an image of a pre-stored picture being displayed on a display interface of the display device ("test picture"). The pre-stored picture includes a first section and a second section. The application module calculates respective lengths and widths of the first and second sections from the test picture. The application module further calculates a display size ratio between the first section and the second section, and adjusts a display size of the first section. The display device is then configured to display the first section in an adjusted size. A screen display ratio adjusting method is also provided.