  TianQin is a proposed space-based gravitational-wave detector mission to be
deployed and operated in high Earth orbits. As a sequel to [Zhang et al. Phys.
Rev. D 103, 062001 (2021)], we investigate a type of ``orbital noise'' in
TianQin's range acceleration that is caused by gravitational perturbation
associated with solar free oscillations. Frequencies of such oscillations are
typically within TianQin's measurement band of 0.1 mHz--1 Hz, and the
disturbance level needs careful assessment. By using high-precision orbit
propagation and adding the Sun's time-variable oblateness $J_2$ to detailed
gravity-field models, we examine the effect in the frequency domain and show
that the solar free oscillation noise is expected to be two orders of magnitude
lower than the noise requirement on single links and hence has little impact on
the mission.
