  Photoelectron spectroscopy in intense laser fields has proven to be a
powerful tool for providing detailed insights into molecular structure. The
ionizing molecular orbital, however, has not been reconstructed from the
photoelectron spectra, mainly due to the fact that its phase information can be
hardly extracted. In this work, we propose a method to retrieve the phase
information of the ionizing molecular orbital with laser-induced electron
tunneling spectroscopy. By analyzing the interference pattern in the
photoelectron spectrum, the weighted coefficients and the relative phases of
the constituent atomic orbitals for a molecular orbital can be extracted. With
this information we reconstruct the highest occupied molecular orbital of
N$_2$. Our work provides a reliable and general approach for imaging of
molecular orbitals with the photoelectron spectroscopy.
