A detection method of an optical navigation device is disclosed. The device is used for determining whether an object is lifted from the optical navigation device or not. The method includes steps of reading the detection image detected by the optical navigation device, calculating the image signal value thereof during non-lift status, and integrating a historical threshold value with the image signal value according to adaptive factors for generating an adjustment threshold value serving as the navigation threshold of the detection image. The historical threshold value is the navigation threshold of a former detection image of the detection image. A step of comparing the adjustment threshold with the image signal value for determining whether the image signal value passes the navigation threshold or not may also be included. If the image signal value does not pass the navigation threshold, the object is determined as in the lift status.