Abstract: An outdoor umbrella includes an awning, a main frame, an illumination system, and an illumination wiring arrangement. The illumination wiring arrangement includes a first wiring unit including a connector plug provided at a first connector end of a first post of the main frame to electrically connect to the illumination system. The second wiring unit includes a power socket which is electrically extended from a power source and is extended through a second post of the main frame at the second connector end thereof to electrically connect to the connector plug, wherein when the first post is coupled with the second post, the power socket is free to move within the second post to keep intact an electrical connection between the power socket and the connector plug even when vibration occurs at the main frame.