Abstract: Disclosed are a support device and a folding furniture having the support device. The support device includes a base, a support mechanism, a fixed seat, and a force providing mechanism installed to the base. The support mechanism includes a support element and a rotating element rotatably installed to the base. The support assembly has an end hinged to the fixed seat and the other end having a disassembling structure for detachably connecting the rotating element. The rotating element abuts the force providing mechanism, and the force providing mechanism is provided for supporting the rotating element. The support device has an ingenious structural design, so that the support element and the rotating element can be installed or removed conveniently, and the operation is simple and labor-saving, and the lifting operation of the support element has the features of stable operation, low noise, and high practicality.