The invention relates to a kieselguhr composite decoration plate and a production process thereof, belonging to the field of building materials. In the invention, kieselguhr is used as a main material to prepare the kieselguhr composite decoration plate and a production process of the kieselguhr composite decoration plate is further provided. The decoration plate is made from the following raw materials: kieselguhr, polyvinyl chloride and processing auxiliaries. According to the invention, based on a series of good characteristics of kieselguhr, such as light weight, soft texture, multiple pores, sound insulation, heat resistance, acid resistance, large specific area, stable chemical property and the like, the produced kieselguhr composite decoration plate has the advantages of low sound,heat and electricity conductivity, zero formaldehyde, water tightness and flame retardance and the like and simultaneously can be nailed, sawed and planed and has other processing characteristics, and thus the kieselguhr composite decoration plate can be widely used for family indoor and outdoor decorations.