  We consider the baryogenesis picture in the Zee-Babu model. Our analysis
shows that electroweak phase transition (EWPT) in the model is a first-order
phase transition at the $100$ GeV scale, its strength ranges from 1 to 4.15 and
the masses of charged Higgs boson are smaller than $300$ GeV. The EWPT is
strengthened by only the new bosons and this strength is enhanced by arbitrary
$\xi$ gauge. However, the $\xi$ gauge does not break the first-order EWPT or,
in other words, the $\xi$ gauge is not the cause of the EWPT. This leads to the
fact that the calculation of EWPT in Landau gauge is enough; and the latter may
provide baryon-number violation (B-violation) necessary for baryogenesis in the
relationship with nonequilibrium physics in the early universe.
