The regional precision atmosphere modeling technology is of great significance to the fast ambiguity fixation of Precise Point Position Real-Time Kinematic (PPP-RTK) technology. The atmospheric delay data of the self-built monitoring station in Xi'an is used as the data source, and the linear fitting method is used as the modeling method to obtain the atmosphere delay in Xi'an and evaluate the accuracy of the model. The results show that it is feasible to use the linear fitting method and the atmosphere delay of regional stations to carry out regional precise atmosphere modeling; the accuracy of the regional atmosphere model obtained by the linear fitting method is 7 mm in the troposphere and 1.44 cm in the ionosphere.