Abstract: The AHP(Analytic hierarchy process) prior distribution fusion method was put forward to estimate the distribution of geotechnical parameters for a small sample in the case of insufficient data by using testing data and some groups of prior distribution data(existing in history) in the same zone.Based on the AHP method and considered by the influence factor to each prior distribution between its prior data and testing data,a hiberarchy model about reliability was established to confirm the weight of every prior distribution.The results show that this method can enhance the steadiness in statistical decision-making and bring about the optimum fitting of probabilistic model of geotechnical parameters.