Abstract: Based on the actual measurement data of 17 field testing architecture groundsill sites,optimization fitting analysis of groundsill settlement versus time curves is carried out.Based on the settlement characteristics of the architecture groundsill,an Usher-Spillman combined mathematical model is put forward.The fitting results of the 17 field measurement data by using the model show that the fitting precision is high,the correlativity coefficient R is in the range of 0.997 68~1,and the average value is 0.999 24.The fitting effect of the model is better than that of the hyperbolic model,the Usher model and Spillman model.Results show that the Usher-Spillman combined mathematical model has a good adaptability and it is accurate and credible for the fitting of groundsill settlement versus time curves.The corresponding fitting equations can be used to forecast the settlement of the architecture groundsill.