  Using a simple analytic method, we calculate the impact effect between the
ejecta of a SN Ia and its companion to survey the influence of initial
parameters of the progenitor's system, which is useful for searching the
companion in a explosion remnant. The companion models are obtained from
Eggleton's evolution code.The results are divided into two groups based on mass
transfer stage. For a given condition, more hydrogen-rich material is stripped
from the envelope of a Hertzsprung-gap companion than that of a main-sequence
companion, while a larger kick velocity and a larger luminosity are gained for
a main-sequence companion. The kick velocity is too low to significantly affect
the final spatial velocity of the companion, which is mainly affected by the
initial parameters of the progenitor systems. The spatial velocity of the
stripped material has an upper limit within the range of 8000 - 9500 km/s,
which only depends on the total kinetic energy of the explosion.The stripped
mass, the ratio of the stripped mass to the companion mass and the kick
velocity of the companion all significantly depend on the initial companion
mass and orbital period. Our model may naturally explain the spatial velocity
of the star G in the remnant of Tycho's supernova, while an energy-loss
mechanism is needed to interpret its luminosity.
