The invention discloses an encapsulating method of a reinforced steel corrosion optical fiber sensor, which is applied to the encapsulation and protection of the reinforced steel corrosion optical fiber sensor under a chloridion erosion environment in the fields of transportation and civil engineering. The encapsulating method of the reinforced steel corrosion optical fiber sensor is characterized in that the method comprises the following steps: (a) preparing encapsulating materials for the reinforced steel corrosion optical fiber sensor; (b) producing encapsulating moulds for the reinforced steel corrosion optical fiber sensor; (c) producing the reinforced steel corrosion optical fiber sensor; (d) encapsulating the reinforced steel corrosion optical fiber sensor; (e) disassembling the encapsulating moulds, wherein a cement mortar is prepared by adopting a mixing proportion of concretes with the same class as that of engineering concretes and without addition of coarse aggregate, a siliceous dust is blended into the cement mortar according to the following proportion to substitute for the coarse aggregate and the mixture is stirred evenly, wherein the blended siliceous dust occupies 8-12 percent of the total amount of the cement mortar and the siliceous dust mixture when the intensity class of the concrete is C30-C50. The encapsulating method of the reinforced steel corrosion optical fiber sensor can more accurately simulate the actual corrosion environment of the reinforced steel bar in concretes and achieves the effect for protecting the reinforced steel corrosion optical fiber sensor.