We designed and synthesized novel photocrosslinking guest-host nonlinear optical (NLO) polymer systems. In the system, guest NLO molecules bearing two photocrosslinking groups such as cinnamate or acrylate double bonds were homogeneously dispersed in the host photocrosslinking polymer matrix. The NLO molecules are then aligned by using the corona poling technique at an elevated temperature and the system was subsequently crosslinked by irradiating UV light. We expect the photocrosslinking keeps the NLO molecules from relaxing to random orientation. Formation of network structure was confirmed by comparing the absorbances of the NLO moiety in the crosslinked film before and after washing the film with methanol or acetone, exhibiting little leaching out of the NLO moiety from the polymer matrix.