An auto-focusing method for use in a device, includes: after performing a manual focusing on a target object through receiving a user operation on the target object in a viewfinder of the device, acquiring first spatial data of the target object; when detecting a change of contents of a view in the viewfinder, acquiring position variation data of the target object; acquiring second spatial data of the target object according to the first spatial data and the position variation data; and performing an auto-focusing on the target object according to the second spatial data.