Abstract: Aiming at the present situation of reservoir protection technology and the requirements of surface ecological environment during drilling in Henan oilfield, the development and performance evaluation of Nanoscale starch reservoir protective materials were carried out in order to study the green, efficient and economical new reservoir protection materials. The preparation process was optimized by laboratory single factor experiment and orthogonal experiment, and the characterization of starch-based reservoir protectant DYB-2 was analyzed by means of laser particle size, infrared spectrum, thermogravimetric difference, X-ray and electron microscopy. Evaluation results show that the synthesized DYB-2 material is microspheric with compact structure and uniform distribution of nano-scale pore channels on the surface. It has the characteristics of both rigidity and flexibility. At the same time, the fluid loss effect is obvious(APIFL is less than 4 mL), the core permeability recovery value is more than 80%, and the membrane compressive strength in low and medium permeability cores is more than 10 MPa, which has a better reservoir protection.