An extrusion-ploughing process was presented to fabricate the integral fin function-surface. Cutting edge inclination angle and rake angle can be calculated from the tools geometry relationship. The description of fins geometry characters was standardized. The experiments show that, when the middle cutting edges inclination angle η is less than 35-, continuous fin will come out; when η is between 35- and 55-, the fins will be saw-tooth ones, and the fins will be torn when this angle is above 55-; when the extrusion angle θ is between 60- and 150-, the fins will appear, or else, the fins will be torn into chips from the base. Forming angle and clearance angle have little effect on fins formation. For continuous fin, its height is close to cutting depth when it is small, but it will become approximately constant as cutting depth grows; for saw-tooth fins, the width, the height, as well as the clearance will increase with the increase of cutting depth, but the increment of clearance is small; neither for continuous fin, nor for saw-tooth ones, cutting velocity has little influence on their structure parameters.