The design criterion of minimum life-cycle cost can’t reflect the subjective risk attitude of decision maker. To remove this deficiency, the utility theory, as a classical decision model, is adopted to investigate the influence of risk aversion on decision-making considering seismic risk. With 12 office buildings with different seismic design levels taken as the examples, the optimal strategies of seismic risk mitigation and seismic risk transfer are studied. Risk mitigation refers to seismic design from the perspective of society (public decision maker), while risk transfer refers to making an earthquake insurance contract from the perspective of property owner (private decision maker). The analysis results show that the optimal seismic design level may increase with the rising degree of risk aversion. Earthquake insurance premium which property owner could accept may increase, with the rising degree of risk aversion and the decrease of seismic resistance of structures.