Poly(amine-ester)-1,8-naphthalimide dendrimer (PAE-1,8-NL) is synthesized from ethylenediamine (EDA), trimethylolpropane triacrylate (TMPTA) and 1,8-naphthalic anhydride, the yield is 32.79%. The structure of PAE-1,8-NL is charactracterized by IR and 1HNMR. The physical performance of PAE-1,8-NL with the lanthanide ions (La3 、Nd3 、Dy3 、Gd3 、Eu3 ）and hydrogen ion is studied by UV spectra and fluorescent spectra. The results show that PAE-1,8-NL in chloroform-ethanol (V:V=1:1) diluent solution excited at 357 nm appears two fluorescence peaks（370nm and 386nm）, assigning to naphthyl monomer emission and intramolecular naphthyl-naphthyl dimmer/exmier emission. The presence of the lanthanide ions and hydrogen ions is found to have a very small effect on the naphthyl monomer emission peak but it has a disciplinarian effect on the intensity of the naphthyl-naphthyl dimmer/exmier emission peak. The enhancement in the fluorescence mainly owes to photoinduced electron transfer effect. Fluorescence of PAE-1,8-NL is first increased then decreased by the lanthanide ions; increased by hydrogen ion; first increased then decreased by the lanthanide ions and hydrogen ion in the solution.