The invention relates to a combined privacy glass composite window and a preparation method thereof. The combined privacy glass composite window comprises a substrate, and a first outer ITO transparent conducting film layer, an electrochromism layer, an ion transport layer, an ion storage layer and a second outer ITO transparent conducting film layer which are arranged in sequence on the outer surface of the substrate, and further comprises an inner ITO transparent conducting film layer and PDLC liquid crystal dimming film which are arranged in sequence on the inner surface of the substrate, wherein common glass, tempered glass, laminated glass, organic glass or a mixture of the common glass, tempered glass, laminated glass and organic glass is selected to serve as the substrate, tungstenoxide is selected to serve as the film material of the electrochromism layer, metal lithium ion film is selected to serve as an ion conducting layer, nickel oxide ion film is selected to serve as theion storage layer. The combined privacy glass composite window has the advantages that the electrochromism layer and the PDLC liquid crystal dimming film are combined, so that the relative merits of the electrochromism layer and PDLC liquid crystal dimming film are combined, thereby being capable of achieving the effects of intelligent dimming and shading.