Polymer dispersed liquid crystal (PDLC) is widely used in projection displays, smart windows and other fields. Patterned flexible smart window based on PDLC would further expand its application. In this paper, a patterned flexible PDLC smart window is demonstrated using one-step UV exposure. The PDLC precursor is sandwiched between two flexible PET-ITO substrates, and a layer of patterned mask with specific UV attenuation is attached on the cell for UV curing. The linewidth resolution of 120 μm is obtained for the proposed patterned flexible smart window. In this paper, the different electro-optic characteristics of the different regions of patterned device are studied. The experimental results show that the PDLC with high UV curing region has high threshold voltage and saturation voltage. The rising times of high UV curing region and low UV curing region are 4.1 ms and 15.4 ms, and the decay times are 14.1 ms and 33.7 ms, meeting the application requirements of smart windows. By applying different voltages, the patterned smart window can present three modes: total scattering state, total transparent state and patterned transparent display state. Finally, the pattered smart window working in plane state and bending state are exhibited in the paper. This study shows that the patterned PDLC flexible device prepared by the above one-step UV exposure has the advantages of simple fabrication, low cost and high precision, which is conducive to its potential applications in the field of customized flexible smart windows.