  The quasiparticle interference (QPI) in Sr$_{2}$RuO$_{4}$ is theoretically
studied based on two different pairing models in order to propose an
experimental method to test them. For a recently proposed two-dimensional model
with pairing primarily from the $\gamma$ band, we found clear QPI peaks
evolving with energy and their locations can be determined from the tips of the
constant-energy contour (CEC). On the other hand, for a former
quasi-one-dimensional model with pairing on the $\alpha$ and $\beta$ bands, the
QPI spectra are almost dispersionless and may involve off-shell contributions
to the scatterings beyond the CEC. The different behaviors of the QPI in these
two models may help to resolve the controversy of active/passive bands and
whether Sr$_{2}$RuO$_{4}$ is a topological superconductor.
