We study complete properties of root vectors of Schrödinger operators. More accurately, denote by B(r 0 ) be the ball centered at the origin with radius r 0 and L 1 (B(r 0 )) the space which consists of real functions f(x) satisfying B(r 0 ) |f(x)|dx < ∞, then the complete properties of eigenvectors for Schrödinger equation are characterized. Our characterization depends on the sum of eigenvalues. Our proof is based on a complex-analytic conjugate approach which is widely used in the investigation of completeness of function systems in Banach spaces.