The switchable second-order nonlinear optical (NLO) properties on two-dimensional (2D) molecules based on Lindqvist-type [Mo6O19](2-) and dithienylperfluorocyclopentene (DTE) have been investigated at density functional theory (DFT) level. The CAM-B3LYP and M06-2X functionals were employed to study the switching behavior on NLO properties by photoisomerization reaction. The beta(tot) value of system 2c (closed-ring form) is 15920.5 au, which is 150.1 times larger than that of the corresponding open-ring form (system 20). The time-dependent DFT calculations predict that the charge transfer from DTE to polyoxometalate, and DTE intramolecular charge transfer in closed-ring systems effectively improve the static first hyperpolarizability. Furthermore, the A-shaped systems possess a larger u value than those of W-shaped systems owing to different orientation for substituent groups.