  We present a detailed pulse phase resolved spectral analysis of the
persistent high mass X-ray binary pulsar Vela X-1 observed with Suzaku during
June 2008. The pulse profiles exhibit both intensity and energy dependence with
multiple peaks at low energies and double peaks at higher energies. The source
shows some spectral evolution over the duration of the observation and care has
been taken to average over data with minimum spectral variability for the
analysis. We model the continuum with a phenomenological partial covering high
energy cutoff model and a more physical partial covering thermal Comptonization
model (CompTT) excluding the time ranges having variable hardness ratio and
intensity dependence. For both the models we detect a cyclotron resonant
scattering feature (CRSF) and its harmonic at ~ 25 keV and ~ 50 keV. Both the
CRSF fundamental and harmonics parameters are strongly variable over the pulse
phase, with the ratio of the two line energies deviating from the classical
value of 2. The continuum parameters also show significant variation over the
pulse phase and give us some idea about the changing physical conditions that
is seen with the changing viewing angle at different pulse phases and
obscuration by the accretion stream at some pulse phases.
