Abstract: Based on the pile foundation of a bridge in northern area of Anhui province, five methods are used to calculate the ultimate bearing capacity of pile foundation after post grouting, including the technical codes for building pile foundations, the respective enhancement coefficients of the friction of pile side and the resistance of pile tip, the enhancement coefficient of the total ultimate bearing capacity, the codes for design of grouting base and foundation of highway bridges and culverts, and the method for bearing capacity which only considers pile tip improvement. The test results are compared with the in-situ values and show that the method of respective enhancement coefficients of the friction of pile side and the resistance of pile tip is adopted preferentially, and the second one is the technical codes for building pile foundations. It is not good to use the method of the codes for design of grouting base and foundation of highway bridges and culverts and the one only considering pile tip improvement.