The properties of nuclei belonging to the newly observed α-decay chain starting from 265Bh have been studied. The axially deformed relativistic mean-field calculation with the force NL-Z2 has been performed in the blockedBCS approximation. Some ground state properties such as binding energies, deformations, spins, and parities, as well as Q-values of the α-decay for this decay chain have been calculated and compared with known experimental data. Good agreement is found. The single-particle spectrum of the nucleus 265 Bh is studied and some new magic numbers are found,while the magnitudes of the shell gaps in superheavy nuclei are much smaller than those of nuclei before the actinium region, and the Fermi surfaces are close to the continuum. Thus the superheavy nuclei are usually not stable. The The methods which give good agreement with the data are selected.