A support assembly for photovoltaic panels, the support assembly comprising a plurality of support units connected one by one, wherein each of the plurality of support units comprises: a support beam, comprising a top portion and a pair of side portions perpendicularly extending from two edges of the top portion respectively, the top portion and the pair of side portions collectively defining a receiving groove; a pair of standing posts, each with one end pivotably mounted on the support beam; a strengthening bar, with two ends mounted to the support beam and one of the pair of standing posts respectively; at least one horizontal beam, with one end pivotably mounted to the support beam, and the other end being configured to connect to a neighboring support unit; and a connecting member used to pivotably mount the pair of standing posts, the strengthening bar and the at least one horizontal beam to the support beam and comprises connecting shafts and cotter pins, and the connecting shafts define a plurality of shaft holes to engage with the cotter pins to prevent the connecting shafts disengaging; wherein the pair of standing posts and the strengthening bar rotate relative to the support beam and are received in the receiving groove respectively, and the at least one horizontal beam rotates relative to the support beam and is disposed in parallel to the support beam, when each of the plurality of support units is packaged; when the support units are assembled, the at least one horizontal beam is connected to the neighboring support unit, the pair of standing posts are unwound and disposed in parallel and, the strengthening bar rotates relative to the support beam to constitute a triangle with the support beam and one of the pair of standing posts collectively. a support beam, comprising a top portion and a pair of side portions perpendicularly extending from two edges of the top portion respectively, the top portion and the pair of side portions collectively defining a receiving groove; a pair of standing posts, each with one end pivotably mounted on the support beam; a strengthening bar, with two ends mounted to the support beam and one of the pair of standing posts respectively; at least one horizontal beam, with one end pivotably mounted to the support beam, and the other end being configured to connect to a neighboring support unit; and a connecting member used to pivotably mount the pair of standing posts, the strengthening bar and the at least one horizontal beam to the support beam and comprises connecting shafts and cotter pins, and the connecting shafts define a plurality of shaft holes to engage with the cotter pins to prevent the connecting shafts disengaging; wherein the pair of standing posts and the strengthening bar rotate relative to the support beam and are received in the receiving groove respectively, and the at least one horizontal beam rotates relative to the support beam and is disposed in parallel to the support beam, when each of the plurality of support units is packaged; when the support units are assembled, the at least one horizontal beam is connected to the neighboring support unit, the pair of standing posts are unwound and disposed in parallel and, the strengthening bar rotates relative to the support beam to constitute a triangle with the support beam and one of the pair of standing posts collectively.