Herein, we review the recent progress in the electron dynamics of optical ionization using ultraintense laser fields. Further, the photoelectron momentum distributions at the tunnel exit during nonadiabatic tunneling ionization are analyzed. The electron angular distributions are obtained in terms of molecular coordinates, allowing the imaging of the molecular inner orbits. The two-color (400 nm+800 nm) circularly polarized laser fields are used to achieve a double-pointer attoclock in which the phase and amplitude of the electronic wavepackets can be characterized. Furthermore, the photoelectrons with a high degree of spin polarization can be produced using circular laser fields based on the ionization of atoms with large spin-orbit coupling effects. Finally, the applications of ultrafast strong field physics and its developmental trend are illustrated.