A 36-year-old patient with Behcet's disease was hospitalized because of severe aortic valve regurgitation accompanied by aortic valve neoplasia and perforation of the valve body. In the first operation, we performed aortic valve replacement and ascending aortoplasty. The regular examination after surgery found no obvious regurgitation or discomfort. Four months later, however, the artificial valve fell off the valve frame and the annulus, with severe perivalvular leakage; the range of detachment was about two thirds. In the second operation, we applied a bovine pericardial patch. The aortic valve annulus was reconstructed using the lower edge of the bovine pericardial patch. The upper edge of the patch was sutured to the top of the aortic sinus to strengthen it, and the lateral edge was sutured 3 to 5 mm from the left coronary opening. The artificial valve was fixed well 6 months after the operation, and no valve detachment was observed. This method of reconstructing an aortic valve annulus with a bovine pericardial patch may be referential for preventing artificial valve detachment in patients with Behcet's disease.