摘要：Social welfare, the ultimate pursuit of medicine patent protection, is aff ected
by multiple market and government factors. This paper constructs a multi-stage
dynamic sequential game model involving the government and medicine enterprises
and integrates various market and government factors into account. Next, the social
welfare of monopoly pricing and government pricing are compared, while the
optimal length and its correlations with the infl uencing factors are determined for
medicine patent. It is concluded that the optimization of medicine patent length is a
complex decision-making process; the optimal patent length is aff ected by pricing
mode, government subsidy, market demand elasticity, R&D investment, marginal
cost, product lifecycle and discount rate. The government should determine
medicine patent length according to local conditions, rationalize medicine pricing
mechanism, and develop a competitive medicine market.
关键词：monopoly pricing; government pricing; optimal patent length; social
welfare; social innovation;
