A valuable document authentication method and device. Whether a valuable document, an image sensor or a first sensor has shifted or not, the effect of authenticating the valuable document will not be affected, because a reference unit is needed to determine the location relationship between the image sensor and the first sensor before the valuable document is authenticated, thereby preventing an error occurring with the authenticated valuable document due to the fact that each sensor has shifted; moreover, when the valuable document is authenticated, even if the valuable document has shifted, the correctness of the valuable document authenticated can also be guaranteed by the conversion of the location relationship between a detection object and the sensor. Therefore, the solution provided in the present invention improves the identification accuracy and working efficiency of the authentication device, thereby providing convenience for users.