Aero-optical aberration wavefront can be represented as a multiplicative summation of the proper orthogonal decomposition (POD) basis functions and time coefficients. So if the basis functions are known, how to obtain the time coefficients real-timely is the key in construction the wavefront. Based on the wavefront′s low order approximation expression, the linear equations set that the time coefficients, basis function′s spatial derivative and the jitters of probe beams are met is established. By solving the linear equations set, the series coefficients are obtained. This approach is applied in the aberration wavefront induced by a heated jet. The results indicate that coefficients obtained by this approach are coincided with those by directed POD analysis of the wavefront time series. The coefficients combined with POD basis functions can reconstruct the wavefront effectively. Because only a few jitters need to be measured among the beam apertures and a few equations need to be solved, so the approach has the potential for real-time coefficients obtaining, sequentially for the fast wavefront reconstruction.