Based on a rigorous far-field solution of the Helmholtz equation,the dependence of the far-field of the light wave with a large divergence angle on the perturbation of the source profile is discussed,and the error formulas of the far-field amplitude and phase are also given.It is shown that the far-field errors must be described by using the “error area” of the source.In the paraxial region,the far-field amplitude and phase are not sensitive to the source perturbation,but,in off-axis region,they may be sensitive.