Mechanical property of ellipsoid pressure vessels with unequal polar openings is studied in this paper. The steady formulas for filament on a surface of revolution are derived from differential geometry. Based on the membrane theory, laminate theory and Tsai-Wu failure criterion, the thickness of the equator is 1. 281 7 mm, the stress value of the fiber direction is less than the fiber strength 3. 92 GPa. The stress state of the filament wound ellipsoidal vessel is that the damage happens first in equator, and local failure phenomenon is happened. To minimum winding layers weight M as the objective function, Tsai-Wu failure criterion as the constraint condition, under the condition of 5 MPa internal pressure, we achieve the optimized weight is 34. 072 kg. Compared to ellipsoid pressure vessels with equal polar openings, it has highly non-linear, instability and high precision.