Although several approaches have been developed to evaluate the target enterprise of merger and acquisition (M&A) such as classical net present value (NPV) evaluation model and real options techniques, the logic of pricing processes in all these approaches is still faulty. The classical approach of NPV perspective to price the target enterprise of M&A has been replaced by integration of contemporary perspectives such as NPV perspective, real options perspective, game perspective, and so on. In this paper, the dynamic analyses model to price the target enterprise of M&A is developed from the perspective of real options integrated with game theory under stochastic surroundings. The synergy multiplication coefficient is introduced into the evaluation model to reflect the synergy management process of M&A, and the equilibrium price formula is proposed by applying the famous offer–counteroffer Rubinstein theorem, which is improved to fit for the stochastic surroundings. The price formula is further discussed on condition that the operating cost is more than or less than profit flow, which is assumed to follow geometric Brownian motion process. The numeric simulations show that the proposed formulas in this paper can perfectly well reflect the realistic practice of M&A.