Random-fuzzy statistical method can be used to reflect the space variation of geotechnical parameters. The method for determining the weight coefficient is discussed. Especially

the significance of “reference point” is studied. The results show that when the reference point limitlessly approaches the core point

the corresponding maximum membership degree is just the desired correct result. Based on the principle of random-fuzzy statistical method

an iterative calculation procedure is proposed to calculate the objective function. To analyze the geotechnical parameters in a certain nuclear power plant project

the curves of membership degree of each rock sample against reference point

as well as the procedure curves of reference point approaching core point

are obtained. The results show that the exponential function well expresses the function of membership degree. The distribution of membership degrees of samples exhibits normal distribution of narrow region. Therefore

the random-fuzzy statistical method is consistent with the practice; and then it is better than the conventional random method.