  We propose that fast radio bursts (FRBs) can be used as the probes to
constrain the possible anisotropic distribution of baryon matter in the
Universe. Monte Carlo simulations show that, 400 (800) FRBs are enough to
detect the anisotropy at 95\% (99\%) confidence level, if the dipole amplitude
is at the order of magnitude 0.01. However, much more FRBs are required to
tightly constrain the dipole direction. Even 1000 FRBs are far from enough to
constrain the dipole direction within angular uncertainty
$\Delta\theta<40^{\circ}$ at 95\% confidence level. The uncertainty on the
dispersion measure of host galaxy does not significantly affect the results. If
the dipole amplitude is in the level of 0.001, however, 1000 FRBs are not
enough to correctly detect the anisotropic signal.
