Based on iterative technique, a novel optimization approach for reconstruction a planar object from a perspective line drawing is proposed. Some constraint relationships between edges of a planar object are deduced and formulated as a linear system. The planar object can be recovered by solving the linear system. If the line drawing is a practical line drawing, the recovered planar object will be re-projected onto the projective plane. And then the parameters of the projection will be weighed with those of the corresponding line in original line drawing. The new linear system can be achieved by substituting the weighted parameters into the original linear system and solved again. This procedure is iterated until the value of an object function is smaller than the threshold predefined. Experiment results show that in addition to the ideal line drawing, the proposed algorithm can be applied to the practical line drawing.