In order to realize target searching of large field of view and target observation of small field of view of coastal photoelectric equipments, based on the research and analysis of the zoom optical system design model and theory parameters, four zoom optical structure of optical compensation method is chosen, and a coastal surveillance infrared optical system of hybrid refractive-diffractive two zoom is proposed. After adjusting the initial structure and optimizing with ZEMAX software, a two zoom infrared optical system is designed, which has 150~300 mm focal length, 100 mm diameter. At the space frequency of 30 lp/mm, the modulation transfer function (MTF) reaches 0.6, the speckle in the full field of view is controlled within 25 μm, and the non-thermal sensitization is realized within the working temperature range of -30℃~+50℃. The system is simple in structure, and the number of lenses is reduced to 5 by using aspheric surface and diffraction surface, and the design results meet various task indexes. It is important to the development of coastal infrared surveillance optical system.