A clock tree circuit includes a clock source and a tree circuit. The clock source generates a signal. The tree circuit at least includes five driving units and a metal connection element. A first driving unit has an input terminal for receiving the signal, and an output terminal coupled to a first node. A second driving unit has an input terminal coupled to the first node, and an output terminal coupled to a second node. A third driving unit has an input terminal coupled to the first node, and an output terminal coupled to a third node. A fourth driving unit has an input terminal coupled to the second node. A fifth driving unit has an input terminal coupled to the third node. The metal connection element is coupled between the second node and the third node, and configured as a short-circuited element.