An outdoor umbrella includes an umbrella post, an umbrella cover assembly and a folding-unfolding device. The umbrella cover assembly includes an umbrella rib assembly and an umbrella fabric covering the umbrella rib assembly. The folding-unfolding device includes a slide sleeve, a folding-unfolding handle assembly and a pull rod. A first oblique rod and a second oblique rod hinged and matched with each other are disposed on the umbrella rib assembly. One end of the first oblique rod is hinged to the slide sleeve. One end of the second oblique rod is hinged and matched with the umbrella post. A middle portion of the folding-unfolding handle assembly is hinged and matched with the umbrella post, and the folding-unfolding handle assembly is able to vertically stretch the pull rod in cooperation with a lever and drives the slide sleeve to slide vertically to fold or unfold the umbrella cover assembly.