The excessive axial load occurred in an immovable zone of continuous welded rail(CWR) tracks threatens the security of running trains due to the track buckling in extreme hot summer. The influence factors, such as rail temperature for compressive stress, ballast resistance for track stiffness and initial imperfection of track for tracks irregularity are uncertain track parameters that are randomly varied by climate conditions, operating conditions and maintenance of track etc. So, buckling of CWR tracks has very high uncertainties. Therefore, applying the probabilistic approach method is essential in order to rationally consider the uncertainty and randomness of the various parameters. In this study, buckling sensitivity analysis was carried out with respect to the characteristics of probability distribution of lateral ballast resistance using the buckling probability evaluation system of CWR tracks developed by our research team.