In the bidding process in the power generation market, enterprises often exhibit speculative behaviors due to the loopholes in bidding rules. To explore the evolution of power generation enterprises from a benign bidding state to a speculative bidding state, an evolutionary game model is established. Based on the replicator dynamics equation, an evolutionary game model of a power generation market containing multiple power generation enterprise groups with different bidding strategies is constructed by introducing the relationship factors of the strategies. Then, to analyze the internal mechanism of the outbreak of speculative behavior, the replicator dynamics equation is transformed into a classical sharp point mutation model. On this basis, Gaussian white noise is introduced to construct the stochastic catastrophe model. The influence of the random disturbance term on the stability of the bidding behavior of enterprises is discussed from the perspective of the trajectory difference between the analytical solution and the numerical solution of the stochastic differential equation. The results show that the final decision state of the group strategy and the convergence time of group evolution to this state depend on the value of the strategy relationship factor. The emergence of random disturbances will lead to heterogeneous decision-making actions within the group. That is, the evolution of the group will fluctuate near the strategic equilibrium point. The difference between the analytical solution and the numerical solution of the stochastic catastrophe model can increase the possibility of a sudden change in the bidding strategy state and thereby decrease the stability of the bidding behavior.