Natural rock’s geomechanical properties are inherently variable so geotechnical engineers are unavoidably faced with decision making under uncertainty. To address the uncertainty involved in a tunnel design, the authors combine both the popular uncertainty analysis techniques (Monte Carlo method and Point Estimate method) and a powerful numerical modeling method by means of a controlling Visual Basic program. With the aid of a Visual Basic program, 1458 2-D Difference Models are executed automatically to address the uncertainty involved in an underground coal mine tunnel design. The combination of both the full tunnel roof deformation distribution obtained from the Monte Carlo method and the general trend provided by the point estimate method can provide useful information about the potential roof deformation of the tunnel with respect to input parameters uncertainty.