Abstract: The application of open caisson structures in urban underground spaces is becoming increasingly widespread. However, existing research on surface settlement are mainly based on fitting field measurement or model test results, and thus have certain limitations. This study utilizes the cylindrical cavity expansion theory to propose a calculation method for the sidewall friction resistance of open caissons. Through numerical simulations, the distribution patterns of surface settlement around circular open caissons are investigated, and corresponding fitting formulas are established. Based on the equivalent sidewall area principle of open caissons, the proportional coefficients for maximum surface settlement of square and rectangular open caissons are obtained. Finally, a comprehensive prediction method for surface settlement around open caissons is developed, and its validity is verified through comparison with field measurement results.