The invention relates to a preparation method for a copper indium gallium selenium film layer of a solar cell. The preparation method comprises the following steps of: a, preparing elements of copper, or copper and gallium in advance on a substrate plate by using a magnetron sputtering method; and b, sequentially evaporating the elements of indium, gallium and selenium or the elements of indium and selenium on the substrate plate in a vacuum evaporation room by using an evaporation method. In the method, the magnetron sputtering method and the evaporation method are combined, the metal elements with higher evaporation temperature are prepared on the substrate plate in advance by using the magnetron sputtering method, and the metal elements with lower evaporation temperature are prepared on the substrate plate in advance by using the evaporation method, therefore, the difficulty of temperature control is reduced, the use of a highly toxic gas of hydrogen selenide is avoided in the evaporation method, it s easy to control the preparation process, the influence of the toxic gas on an operator can be avoided.