The invention discloses a passive optical fiber switch of an intelligent substation and a safety measure isolating method thereof. The passive optical fiber switch comprises an optical fiber collimator, the two ends of the optical fiber collimator are provided with two optical fiber adapters which are partially embedded in the optical fiber collimator, the optical fiber adapters are connected with optical fibers, a blocking plate is arranged in the optical fiber collimator, the optical fiber collimator is divided by the blocking plate into a left part and a right part, and a trigger switch is connected with the blocking plate. The defect of poor visibility of a soft pressing plate in safety measure isolation can be overcome, and the risk of error wiring caused by plugging and pulling of the optical fibers for safety measure isolation and the hidden risk of damage to the optical fiber interface can be eliminated. No operation of an electronic device is needed, the influence of interference of an external electromagnetic field can be eliminated, the reliability is high, and the method is the same as the safety measure method of the conventional substation. An obvious disconnection point is provided, the implementation and restoration of the safety measure method is simple and convenient, safety requirements of conventional repair and maintenance can be satisfied, and the working efficiency, reliability and safety can be improved.