Magnetic fields play a crucial role in the star-forming process by supporting clouds or clumps against gravitational collapse. The interplay between magnetic field, gravity, and turbulence can influence types of core fragmentation, e.g., no, aligned, and clustered fragmentations (Tang et al. 2019). G28.34+0.06 (G28.34) is a massive star-forming region which contains filamentary structures and a massive northern clump (hub). We estimate magnetic field orientations and strengths at the northern clump using dust polarization observations towards G28.34 obtained by SCUBA-2/POL2 on the JCMT. Magnetic fields in cores fragmented within clumps have been studied using ALMA observations (Liu et al. 2020). We compare magnetic field orientations at the clump and core scales. We also estimate the distribution of magnetic field strengths and mass-to-flux ratios to show relative importance of magnetic field compared to gravity within the clump. The magnetically super-critical regions in the clump are consistent with core position obtained by ALMA. Our results contribute to understanding the role of magnetic fields in core fragmentation.