The invention relates to a composite material cabin cover and a preparation method thereof. The cabin cover comprises a left top cover body and a right top cover body which are oppositely distributed; the left side of the left top cover body is connected with a left side cover body; the right side of the right top cover body is connected with a right side cover body; a left top cover rear cover body, a right top cover rear cover body, a left side cover rear cover body and a right side cover rear cover body are correspondingly fixed to the rear ends of the left top cover body, the right top cover body, the left side cover body and the right side cover body; and the left top cover body, the right top cover body, the left side cover body, the right side cover body, the left top cover rear cover body, the right top cover rear cover body, the left side cover rear cover body and the right side cover rear cover body all use a composite material, and are integrally formed and manufactured in a vacuum resin leading-in manner. The composite material cabin cover has the beneficial effects of being simple in structure, low in cost, safe and reliable, and the lightweight purpose is achieved on the basis that the loading strength is guaranteed. The preparation method of the cabin cover has the beneficial effects that the process is simple, implementing is easy, and the production efficiency is high, and batch production is facilitated.