The present invention provides a fluorinated conjugated microporous polymer providing good absorption capacity for heavy metal ions in a water body, and a preparation method thereof. The fluorinated conjugated microporous polymer is prepared by respectively carrying out catalysis copolymerization on 1,3,5-trifluoro-2,4,6-triethynylbenzene or 1,3,5-triethynylbenzene, wherein the specific surface area is about 700-1000 m<2>/g, the contact angle of the surface water is 155-167 DEG, the polymer provides selective absorption ability (only absorbs heavy metal ions, and does not absorb water) for heavy metal ions in the water body, the re-use performance is good, and the absorption capacity on heavy metal ions such as Cu<2+>, Ni<2+> and Cd<2+> is 0.07-0.18 mmol/g. According to the present invention, the material preparation process route is simple, the operations are easy, advantages of high absorption capability, high selectivity, good dynamics absorption property, good re-use property and the like are provided when the material is applied for heavy metal ion absorption in the water body, and the polymer has potential application values in the fields of crude oil leakage treatment, industrial inorganic wastewater treatment, liquid/liquid separation, water treatment and the like.