Abstract: A series of Nvinylcarbazole(NVCz) labeled methacrylic acid(MAA)acenaphthylene(ACE) copo-lymers(PMAAACE/NVCz),with ACE content of 4.3,7.5,15.1 and 20.8 mol％,respectively,and a ACEMAA copolymer(PMAAACE) with ACE content of 0.5 mol％ have been synthesized. The fluorescence properties of the dilute aqueous solutions of the copolymers and the effect of pH,surfactants upon the properties have been studied in some detail. It was demonstrated that the hypercoiled conformation of the copolymers at low pH made their fluorescence emission to be dominated by ACE excimer and/or NVCz emission. At higher pH,however,the copolymers adopted an extended coil conformation that decreases significantly the efficiency of nonradiative energy transfer from ACE to NVCz. And therefore,the fluorescence emission of the copolymers at higher pH lacked the characteristics of NVCz. Introduction of surfactants had a significant effect upon the fluorescence properties of the copolymers. At low pH,adding any of sodium dodecyl sulfate(SDS),ammonium hexadecyl trimethyl bromide(AHTB) and Tween 80 decreased the efficiency of nonradiative energy transfer from ACE to NVCz due to partially extension of the copolymer coil,and thereby reduced NVCz characteristics in the fluorescence spectra of the copolymers. At higher pH,AHTB,a cationic surfactant,increased the efficiency of nonradiative energy transfer from ACE to NVCz due to partial neutralization of the negative charges along the copolymer chains,and thereby NVCz emission appeared in the fluorescence spectrum of the copolymer. The introduction of SDS or Tween 80 had little effect upon the fluorescence emission of the copolymers at higher pH.