The forecast of underground water level can provide scientific basis for the ecological environmentalprotection，planning and management of underground water resources.According to the similarity between thesamples of underground water level and the characteristics of regularity as well as the both certain and uncer-tain between the impact factors and underground water level，this study set up the similar forecast models ofunderground water level based on set pair analysis,which describe quantitatively the similarity among the his-torical samples of forecast object from the views of identical，discrepancy and contrary sides，combining set pairanalysis with the similar forecast. Further，the predictive values of underground water level can be calculated bythe model. The empirical results suggested that average relative error of the similar forecast models of under-ground water level based on set pair analysis was less than 3%.Compared with other underground watet level prediction methods，this model has the characteristics of clear physical concepts，simple computation and higherprediction accuracy.