The invention discloses a material preparation process suitable for preparing dissolving pulp by modifying natural color unblenched needlebush and broadleaf wood composite paper pulp. The process comprises the processes of preparing raw materials, dispersing, slicing, impregnating and the like. Aiming at the natural color unblenched needlebush and broadleaf wood composite paper pulp raw materials, the special process steps and process control parameters thereof are adopted; the aims of improving the quality of the finished product, saving energy and reducing emission can be fulfilled; the content of alpha cellulose, the yield and the whiteness of the finished product are improved; the ash content is reduced; the material preparation process is beneficial to the cost control of chemical industrial liquid medicine; a subsequent cooking and heating curve is stable; the concentration is uniformly reduced; and the prepared semi-finished product can be suitable for various cooking modes and has wide application range.