N-p-B rPhMA was synthesized by the interaction of p-bromoaniline with methacryloyl ch-loride in the presence of triethylamine．This new monomer was characterized by IR and 1H-NMR spectroscopy．The N-P-BrPhMA-co-MMA bulk copolymers were prepared and characterized by IR and 1H-NMR method．The compositions of the copolymers were determined from the areas of the phenyl gro-up and methoxy group proton peaks in the proton NMR spectra．Reactivity ratios were calculated from the composition data by the Fineman-Ross meth-od；the following values were obtained：r1=3.25+0.02(MMA)，r2=0.40+0.02(N-p-BrPhMA) for MMA-co-N-p-BrPhMA，r1=1.05+0.02(MMA)，r2=0.54+0.02(N-PhMA) for MMA-co-N-PhMA．The MMA-co-N-p-BrPhMA bulk copolymers are harder than PMMA homopolymer．When the amount of the N-p-BrPhMA chlanges from 2.63％ to 28.7％ the hardness of the bulk copolymers increases from 20.4 Kg／mm2 to 27.0 Kg／mm2．