The invention discloses a curvature measuring method and apparatus. The method comprises: a reference point position of a rotational freedom degree of a displacement sensor is set by using a normal direction of a first target point as a reference; the displacement sensor is controlled to rotate within a first preset angle based on the reference point position and measurement is carried out to obtain an absolute distance between the rotation center of the displacement sensor to the first target point; discrete processing is carried out on a to-be-measured object to obtain a preset number of second target points, a corresponding first Cartesian coordinate value when the displacement sensor measures each second target point and a first measurement value outputted by the displacement sensor, and a second Cartesian coordinate value of each second target point is calculated based on the first Cartesian coordinate value, the first measurement value and the absolute distance; and the curvature of each second target point is calculated based on the second Cartesian coordinate values. Because the Cartesian coordinate value of any point on the curved surface can be accurately calculated, the accuracy of curvature measurement is improved; and the measurement is more convenient and flexible.