Endoscopic navigation method and endoscopic navigation system

An endoscopic navigation method includes the steps of: receiving an image from an endoscopic navigation system; performing image classification to determined whether the image is usable; performing a first image process on the image to filter out dark areas of the image to produce a first processed image; performing a first determination procedure to identify the dark areas of the first processed image; producing a first result image for indicating lumen direction; performing a second image process to filter out fold curves of the image to produce a second processed image when there is no dark area in the image; performing a second determination procedure to identify the fold curves of the second processed image; producing a second result image for indicating lumen direction according to the fold curves; and outputting the first or the second result image to a display device to assist users in operating the photographic device.