In this paper, some experimental results are obtained from the application of probabilistic dispatching method to the static job-shop scheduling problem. The following become clear after the investigation made into the optimal parameter and the optimal number of schedules. The optimal parameter lies in the range [0.60,0.80] in case dispatching rule MWKR is used, and in [0.84,0.98] when LWKR rule is used. The range of optimal parameter for LWKR rule becomes narrow as the number of jobs per number of machines increases. It is sufficient to make 15〜25 schedules for the practical use of each rule.