The past decades have witnessed the remarkable development of the optical communications and optical networking. In response to the ever-increasing demands for larger bandwidth and enhanced routing flexibility of optical network, the wavelength selective switch (WSS) was assumed as a critical role in wavelength control and flexible/elastic optical networking. Here, we proposed an integrated all optical lithium-niobate-on-insulator (LNOI) WSS including a 1 × 4 micro ring resonators (MRRs) in the C-band. A non-volatile wavelength-selective tuning process fully controlled by intense light at cryogenic temperature was introduced based on the photorefractive effect. This offers the possibility of realizing of next generation large-scale wavelength division multiplexing (WDM) network and optical add-drop multiplexer (ROADM) system.