The invention relates to an emulsifier for high-iron emulsified asphalt and a preparation method thereof. The emulsifier comprises the following raw materials in part by weight: 35.6 to 63.0 parts of alkylamine emulsifier, 20.2 to 38.3 parts of polyxyethylated alkylphenol emulsifier, 0.3 to 1.1 parts of aid 1, 0 to 1.0 part of aid 2 and 5.0 to 8.0 parts of aid 3. The emulsified asphalt prepared from the emulsifier can be used in a relatively wide temperature range and can be cooled rapidly without breaking emulsion. The emulsifier has the outstanding characteristics that: an emulsifier which is suitable for different temperature environments can be compounded by adjusting the composition proportion of the emulsifier and the problems of poor thermal stability of the high-iron emulsified asphalt and easy emulsion breaking are solved; and the emulsifier has high thermal stability, a small using amount and a wide application range, is easy and convenient to operate during use, can be prepared into high-stability high-iron emulsified asphalt and can lower the cost of an emulsion additive by about 20 percent.