The pressure sensing mode of panda fiber gratings is built using the finite element method and the stress distribution induced by pressure is analyzed. The experimental results show that the peak separation of Panda fiber gratings increases with pressure, and -4.08 pm/MPa the pressure sensitivity along fast axis is stronger than that -3.5 pm/MPa along slow. The influence of fiber structure on pressure sensing characteristics is studied through theoretical calculation and experimental measurement, and the results show that the pressure sensing coefficients of panda fiber gratings are linear with the square of the ratio of radius to distance of stress applied zone. The contrastive experimental results show that the Panda fiber grating cannot be used to measure thermally-insensitive pressure through testing its peak separation.