The α-decay properties of even-Z nuclei with Z = 120, 122, 124, 126 are predicted. We employ the generalized liquid drop model (GLDM), Royer's formula, and universal decay law (UDL) to calculate the
-decay half-lives. By comparing the theoretical calculations with the experimental data of known nuclei from Fl to Og, we confirm that all the employed methods can reproduce the
-decay half-lives well. The preformation factor
and
-decay energy
show that
120,
122, and
124 might be stable. The
-decay half-lives show a peak at Z = 120, N = 184, and the peak vanishes when Z = 122, 124, 126. Based on detailed analysis of the competition between
-decay and spontaneous fission, we predict that nuclei nearby N = 184 undergo
-decay. The decay modes of
120,
122,
124, and
126 are also presented.