The measurement of pressure and temperature in oil well is an important part of intelligent completion system.In order to realize single point and double parameter measurement of pressure and temperature in downhole environment,and the maximum pressure can reach 30 MPa and the temperature can reach 120 ℃,a pressure and temperature sensor with π phase shift grating in center-shaped side hole fiber (SHF) is proposed in this paper.Firstly,the theoretical derivation of simultaneous measurement of pressure and temperature with side hole π phase shift fiber grating is carried out to prove the theoretical feasibility of simultaneous measurement of pressure and temperature.Secondly,based on the theory,the SHF is simulated and optimized,and the fracture limit is introduced.The optimal size of the SHF is obtained as 27 μm from the center of the hole and 21.5 μm from the radius of the hole.The results show that the SHF can realize the measurement of single point and double parameters,and the introduction of π phase shift grating improves the measurement resolution.The larger the hole radius of the SHF,the closer the hole to the core is,the higher the pressure sensitivity,but considering the fiber fracture,the larger the radius is not the better.This research has guiding significance for the design of edge hole grating pressure and temperature sensor in a specific pressure measurement range.