  Coriolis effect is an important error source in the weak equivalence
principle (WEP) test using atom interferometer. In this paper, the problem of
Coriolis error in WEP test is studied theoretically and experimentally. In
theoretical simulation, Coriolis effect is analyzed by establishing an error
model. The measurement errors of Eotvos coefficient (eta) in WEP test related
to experimental parameters, such as horizontal-velocity difference and
horizontal-position difference of atomic clouds, horizontal-position difference
of detectors and rotation compensation of Raman laser's mirror are calculated.
In experimental investigation, the position difference between Rb-85 and Rb-87
atomic clouds is reduced to 0.1 mm by optimizing the experimental parameters,
an alternating detection method is used to suppress the error caused by
detection position difference, thus the Coriolis error related to atomic clouds
and detectors is eliminated to 1.1E-9. This Coriolis error is further corrected
by compensating the rotation of Raman laser's mirror, and the total uncertainty
of eta measurement related to Coriolis effect is reduced as 4.4E-11.
