A rotation stopping structure of a height-adjustable round tube device and a linear driver using same. The rotation stopping structure comprises a fixed base (1), a first telescopic tube (2) formed by several round tubes (21) fitted together, and a second telescopic tube (3) formed by several tubes (31) having polygonal cross-sections fitted together; the second telescopic tube (3) is disposed in the first telescopic tube (2); an innermost round tube (21) of the first telescopic tube (2) has one end fixedly connected to a base (1) and the other end fixedly provided with a first inner lining (20); the first inner lining (20) is provided with a first through hole (201) allowing an outermost sleeve (31) to pass through; the inner wall of the first through hole (201) is in contact with the outer wall of the outermost sleeve (31); and the sleeves (31) are fixedly connected to outer telescopic round tubes (21) in one-to-one correspondence. The linear driver has a simple structure, and the production cost is reduced.