Machining method of complex profile part

The invention discloses a machining method of a complex profile part. The machining method comprises the following steps that rough machining is carried out on raw materials to form a polyhedral structure blank; any plane of the blank serves as a supporting plane for supporting profile machining, the blank is pressed and positioned on a machining machine tool, and a side profile of the part is machined on one side face, opposite to the supporting plane, of the blank; molten low-melting-point alloy is poured into the profile of the blank so as to fill the profile of the blank into a plane; theblank is turned, the original plane on the other side of the blank or the plane formed by pouring the low-melting-point alloy is taken as a supporting plane, the blank is pressed and positioned on themachining machine tool, and a side profile of the part is machined on a plane, opposite to the supporting plane, on the blank until all the profiles of the part are machined; and the low-melting-point alloy on the profiles is