Disclosed herein is a method and system for measuring a tilt angle while a vehicle is turning according to a lateral acceleration and a yaw rate occurring while a vehicle is turning, the method including calculating, by a controller, a traveling acceleration based on a vehicle speed detected by a vehicle speed sensor; detecting a longitudinal acceleration of a vehicle by a longitudinal acceleration sensor; calculating a first tilt angle of the road based on the traveling acceleration and the longitudinal acceleration; detecting a yaw rate of the vehicle by a yaw rate sensor; determining when a value of the detected yaw rate is equal to or greater than a predetermined value; and calculating a second tilt angle to apply a compensation value to the first tilt angle in response to detecting the yaw rate equal to or greater than a predetermined value.