This monk is demonstrating a technique learned from the Monkey King, a legendary master of the staff. Monkey style kung fu has many subvariants, including Drunken Monkey, Stone Monkey, and Standing Monkey. All of them are inspired by the behaviors of other primates.
The staff is probably the most useful of all martial arts weapons. In addition to being a weapon, it can be used as a mountain-climbing aid or a vantage point, as shown here.