Hi hao qiqi0, in IPR mode to make displacement working you need to click "Tesselate" button (in displacement settings) or Tess button in IPR window each time you change displacement settings or change camera position or image resolution. This simple manual work is needed to prevent from constant consuming object tesselation when you actively change the settings and because displacement object tesselations depend on camera parameters too (they are adaptive for viewer position).
Of course, in Picture Viewer mode clicking Tess button is not needed because this is done automatically.

As for displacement settings. You have checkbox "Adapt to pixels" enabled. This means that the tesselation mode (triangle sizes) inside the camera will be adaptive to the distance from camera to surface point. In this case the option Edge size [pixels] is taking effect. Each resulting triangle size will be of the size close to "Edge size [pixels]". It's wise to make the value 1 pixels or 0.5 pixels for production and 2 pixels for testing purposes.
Edge [world] is used when the value "Adapt to pixels" is off.
Remove the texture from Displacement Alpha. This slot accepts the texture to determine the mask of area where displacement mapping texture is applied.

If displacement isn't visible try to make Height value larger and Waterlevel zero. Also at first try to test the displacement texture on a plane to get the idea on sizes and scales. Then apply it for the bottle object.
If nothing still doesn't work then please send this scene file with displacement texture to me to info@centileo.com, I will figure out what is going on there.