One porphyrin covalent organic polymer (PorMeO-COP) via Schiff base condensation using 5,10,15-tris(4-aminophenyl)porphyrin and 2,5-dimethoxyterephthaladehyde as the monomers have been designed and synthesized for fluorescence sensing of water content in organic solvents. The resulting PorMeO-COP display significant fluorescence enhancing upon the addition of different amount of water in eight common hydrophilic solvents. The sensing ranges are achieved over 0.2–6%, 1–20 %, 0.2–15 %, 1–16 %、1–40 %、2–10 %、4–14 % and 0.2–25 % (v/v) for water in methanol, ethanol, acetonitrile, acetone, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide and 1,4-dioxane, respectively, and the limit of detection (LOD) are 0.032 %, 0.076 %, 0.054 %, 0.007 %, 0.014 %, 0.037 % and 0.024 % (v/v), respectively. These findings reveal PorMeO-COP can serve as fluorescence sensor to detect water content in organic solvents.