The invention provides an open type clamp system for an aviation complex part. The open type clamp system comprises a foundation plate (1), process bosses and a plurality of compressing blocks, wherein the foundation plate (1) is fixed to a workbench of a machine tool, the process bosses and the compressing blocks are all fixed to the foundation plate (1), and the aviation complex part (7) is positioned and compressed on the foundation plate (1) through the process bosses and the compressing blocks. An application method for the clamp system comprises the steps that in the machining process, the aviation complex part is firstly positioned on a long-strip-shaped boss and a cylindrical boss through fasteners, and then the end parts of the aviation complex part are compressed through the pressing blocks so as to fix the aviation complex part on the foundation plate. According to the open type clamp system and the application method, the time in the tooling and the aligning processes can be shortened, the interference possibility of a tool and a clamp in the machining process can be decreased, meanwhile, the machinable area of the aviation complex part can be increased, and the method is different from a traditional clamp multi-point orientation and multi-point constraint method.