At present

the surface settlements of deep foundation pit excavation in soft soil can be estimated by regarding the surface settlement curves as normal distribution and skew distribution respectively. The two methods mentioned above are suitable but complicated due to computing the envelope areas of the surface settlement curves. The uncertainties of the results increase at the same time. Thus

improvement has been made for the two methods based on empirical relations to simplify the computation process. The surface settlements of four engineering cases have been computed using the improved methods; and further comparison between the two methods has been performed on based computing results. The results show that the improved methods for computing surface settlements are more simple and practical; and it is better to compute the surface settlements by regarding the surface curve as skew distribution.