Abstract: A belt post includes a post with a box on a top of the post and a reel of belt is received in the box. A spring box is engaged with the top of the box and the mandrel of the reel is engaged with the spring. A head assembly is connected to a distal end of the belt and includes a movable piece which is retractably received in a body with a spring biased therebetween. The head assembly is easily to be engaged between a top cap and a bottom cap of another box by pushing the movable piece to change the length the combination of the body and the movable piece.