The invention discloses a flexible support device for steeply inclined coal seams, which belongs to the technical field of coal mine support machinery. It includes a left support plate, a left top plate, a right top plate, a right support plate, a left hydraulic cylinder, an upper hydraulic cylinder and a right hydraulic cylinder. The left support plate is hinged to the left top plate, the left top plate is hinged to the right top plate, the right top plate is hinged to the right support plate, the left support plate is hinged to one end of the left hydraulic cylinder, the other end of the left hydraulic cylinder is hinged to the left top plate, and one end of the upper hydraulic cylinder It is hinged with the left top plate, the other end of the upper hydraulic cylinder is hinged with the right top plate, one end of the right hydraulic cylinder is hinged with the right top plate, and the other end of the right hydraulic cylinder is hinged with the right support plate. The invention provides a flexible support device for steeply inclined coal seams on the basis of ensuring stable supporting force, easy operation, and the supported mineway is not prone to roof leakage and is easy to carry, so as to provide more efficient support for coal mining under the condition of steeply inclined coal seams. Safe and reliable support cover.