The invention provides a method for detecting the transmitted wavefront at an out-of-focus position of an any-wavelength optical system. The method comprises the following steps: before detecting theZernike coefficient of an optical system by using a laser interferometer, detecting the variation coefficient ki(lambdam) of unit-length Zernike coefficient of the optical system by using the laser interferometer, to obtain a formula shown in the specification; measuring the Zernike coefficient of the optical system by using the laser interferometer, to obtain the Zernike coefficient of the optical system at the focus position, and then obtaining a formula shown in the specification; substituting the abovementioned two formulas into a formula: Zi(lambdam, d)=Zi(lambdam)+ki(lambdam)*deltad, wherein since deltad can be measured, the Zernike coefficient at the out-of-focus position of an any-wavelength optical system can be obtained; and fitting to obtain the transmitted wavefront at out-of-focus position of an any-wavelength optical system. By calculating the transmitted wavefront at out-of-focus position of an any-wavelength optical system by the above method, the error caused by the actual working position deviating from the focus position is greatly reduced.