A linear evaporation apparatus includes a thermal insulation chamber, and crucibles, evaporation material heaters and a mixing chamber installed in the thermal insulation chamber. The mixing chamber includes a flow limiting and adjusting layer, a flow channel adjusting member, a mixed layer and a linear evaporation layer. The flow limiting and adjusting layer is a rectangular sheet with flow limit holes corresponsive to the crucibles respectively; the flow channel adjusting member is an interconnected structure having at least one flow inlet corresponsive to some of the flow limit holes and at least one flow outlet, and the mixed layer is a substantially I-shaped sheet structure, and the linear evaporation layer is a rectangular sheet having a linear source evaporation opening tapered from both ends to the middle, so as to improve the uniformity of the thin film and the utilization of the evaporation materials.