The present invention discloses a portable terminal that measures a reference tilt and a method of measuring the reference tilt using the same. The portable terminal includes a movement sensor for measuring a tilt of the portable terminal using a gravitational acceleration value, and a controller for dividing a preset time into separate time sections and measuring an acceleration value in each separate time section by using the movement sensor, calculating a standard deviation of the accelerations in each separate time section and determining one time section in which movement is minimal, and calculating a tilt of the portable terminal from an average of the accelerations in the determined one time section or a sum of weight acceleration values therein and setting the calculated tilt as the reference tilt of the portable terminal.