Poly(N-isopropylacrylamide) copolymers with side chain of pyrenyl group were synthesized by radical solution copolymerization of N-isopropylacrylamide (NIPAM) and β-pyrenebutanoyloxyethyl methacrylate (PyBEMA). The structure of the copolymers was characterized by IR, UV and 1H NMR spectra. The effects of different feed ratios on the yield, composition, relative molecular weight and distribution of copolymers were investigated. The results of the copolymers aqueous solutions show that the as-synthesized copolymers are a kind of thermosensitive polymers with lower critical solution temperature (LCST), and its LCST decreases with the increase of the pyrenyl content in the copolymers. Addition of α-cyclodextrins (α-CD) will cause a slight increase in LCST of copolymers, while addition of β-CD and γ-CD will cause a decrease in LCST, and γ-CD will cause a more significant decrease in LCST. The fluorescence properties of copolymer aqueous solutions show that the copolymers have slight hydrophobic aggregation in water because it exists of pyrenyl excimer fluorescence. At room temperature, the addition of β-CD can reduce the hydrophobic aggregation of pyrene groups in the copolymer side chains. With the increase of temperature, the fluorescence intensity (IM) of pyrenyl monomer first decreased, then suddenly increased, then reached a stable and slightly decreased. However, the fluorescence intensity (IE) of pyrenyl excimer first increased slightly, then remained basically unchanged, and then decreased slowly. The ratio of I1/I3 decreased with the increase of temperature, and decreased suddenly in the temperature range when the polymer phase transition occurred.