A method and apparatus for determining the attitude of an object is provided herein. The method for determining the attitude of the object comprises: receiving a gravity acceleration signal and a geomagnetic field signal, the gravity acceleration signal and the geomagnetic field signal changing with the attitude of the object accordingly; determining a gravity field representation in an object coordinate system according to the gravity acceleration signal, and determining a geomagnetic field representation in the object coordinate system according to the geomagnetic field signal; calculating a conversion parameter of coordinate system between to the object coordinate system and a terrestrial coordinate system according to the gravity field representation and the geomagnetic field representation in the object coordinate system; and determining the attitude of the object according to the conversion parameter of coordinate system.