Ok, thanks guys i found the solution. For all those who have same probs as me (may be not many ) In edit tile set, click the Terrains icon, the picture icon next to the blue rect and circle, then add custom properties for tile in there.
In fact, the important bit is that you should not open the Tile Collision Editor. This is a common stumbling block since it means you’re adding custom properties to the implicit “Object Layer” attached to a tile for adding collision shapes.
In the upcoming release of Tiled I will take out this functionality since it serves no real purpose and has already confused multiple people. It just isn’t entirely trivial so I haven’t yet found the best way to remove it.