A footstand mechanism for adjusting a tilt angle of an electronic device includes a shaft, a first engaging member, a polygonal block and a second engaging member. The shaft is rotatably disposed on a base of the electronic device, and the first engaging member is disposed on the base and located in a position corresponding to an end of the shaft. The polygonal block is installed on the shaft and rotates with the shaft. The polygonal block includes a plurality of supporting surfaces, and the plurality of supporting surfaces is respectively away from the shaft by different distances. The second engaging member is disposed at the end of the shaft and includes a plurality of engaging portions. The plurality of engaging portions is corresponding to the plurality of supporting surfaces for respectively engaging with the first engaging member.