For the defects of complex process, low forming precision and poor production quality during the drawing process of large slenderness ratio cylinders with concave bottom formed by tailor welded, the composite spinning method combined with the conventional spinning and power spinning was put forward, and the integral manufacturing of large slenderness ratio cylinders with concave bottom was realized. The deformation assignment principle of the composite spinning was obtained by the theoretical analysis, and the concave bottom was spun by spinning wheel locus combining circular-arc in the conventional spinning and straight line in the power spinning. Then, under the condition that the spinning coefficient was larger than the limit spinning coefficient, the blank was obtained by the drawing and spinning. Finally, circular-arc and straight in the shield were spun to thin a certain degree by circular-arc and double-tapered rollers respectively, and the qualified cylinders with the slenderness ratio of 2.01 and concave bottom was produced. At the same time, the production efficiency is increased over 50%. Thus, a new manufacture method of the large slenderness ratio cylinders with concave bottom is provided for industrial batch production.