Summarizing the various numerical methods for computing the Thies well-function, the advantages and disadvantages of each method were analyzed and compared, and their impacts on final model parameter estimation were concluded, a new simplified alternative way was proposed too. Two real examples were adopted to examine the performance of both well-function computation and model auto-calibration. The study results show that: (1) The wide-used series expansion method for calculation of Thies wellfunction should be thinked for use with much caution; (2) Universal optimization platform 1stOpt can be considered as an advance tool for parameter auto-calibration of Theis well-model, and the platform could also be widely applied on other hydrological models.