A model for calculating the wind power penetration limit with transient stability constraints is presented based on fuzzy random chance constraints programming. The uncertainty of wind power output and load are treated as fuzzy random variables. According to the relationship between generation output and the corner, the transient stability constraints are converted into inequality constraints of active power outputs of the generators. The model is computed by genetic algorithm and time-domain simulation method. Test results on the IEEE 14 system are given to verify the transient stability constraint is one of key constraints for wind power penetration limit.