Improving the casing centering degree is the key to ensure the cementing quality. In recent years, with the continuous expansion of the development scale of unconventional oil and gas horizontal wells, the center optimization has become the key issue in cementing design. A casing centring optimization method was developed based on the model modification for the professional standard 《SY/T 5724-2008 Casing String Sructure and Strength Design》, mechanical performance parameters test for the elastic centralizer, accurate acquisition of friction coefficient between different types of centralizer and borehole, and combining with the centralizer placement practice of oilfield. It has been applied in deep horizontal well TK156H of Shunbei oilfield， the practical application shows that the calculation error of this method is within the allowable range of engineering.It is helpful to guide the casing centralizer placement design of deep horizontal wells in Shunbei oilfield, and it helps to ensure the safety of running casing and insure the centering degree in horizontal wells.