Frequency stability is a main criteria for determining the feasibility of a black start scheme. If the blackstart source is a hydropower unit, its water hammer effect will have a significantly negative impact on the frequency stability. It has been proved that the governor parameter optimization is an effective way to reduce the impact. Therefore, based on the characteristics of hydropower units and their governors, this paper selects out the main governor parameters that affect the frequency stability firstly. A multiscenario model of blackstart schemes is built to improve the suitability of optimized parameters. Then, a multiobjective multiverse optimization algorithm is employed to optimize the parameters globally and produces the Pareto optimal set. By adopting the fuzzy entropy method and multiattribute decision making based on gray relational model, the most satisfactory parameter combination is then chosen from the Pareto optimal set. Finally, a provincial power grid in southwest China is taken as an example, the validity and applicability of the method proposed in this paper are verified.