A scroll-rotation prevention assembly of a scroll compressor includes a fixed scroll, an orbiting scroll and an Oldham ring. The fixed scroll is positioned in the compressor and has a body. Two blocks extend from the periphery of the body. The orbiting scroll is disposed to correspond to the fixed scroll and has a main body. Two protrusions extend from the periphery of the main body. The Oldham ring is sandwiched between the body of the fixed scroll and the main body of the orbiting scroll. The Oldham ring has a first surface provided with a pair of first troughs and a second surface opposite to the first surface. The second surface is provided with a pair of second troughs. Each protrusion is slidably connected in the first troughs. Each block is slidably connected in the second troughs. Thus, the wear of the Oldham ring can be reduced.