As a financial instrument for hedging risk, financial transmission right (FTR) has been put into application in some power markets. Based on AC optimal power flow (OPF) a new FTR auction model was proposed under considering of the contingency constraints. With the n-l static security constraints, this model is solved by the AC-OPF based on Monte Carlo simulation. Firstly the contingency set is selected by the probabilistic algorithm, and then the expected values of clearing results and frequency distribution plots are obtained through the optimization results. The numerical results of IEEE 30-bus system demonstrate the rationality and feasibility of the proposed model.