  In this invited talk, I first discuss the advantages and disadvantages of
many probes for the magnetic fields of the Milky Way. I conclude that pulsars
are the best probes for the magnetic structure in our Galaxy, because magnetic
field strength and directions can be derived from their dispersion measures
(DMs) and rotation measures (RMs). Using the pulsars as probes, magnetic field
structures in the Galactic disk, especially the field reversals between the
arms and interarm regions, can be well revealed from the distribution of RM
data. The field strengths on large scales and small scales can be derived from
RM and DM data. RMs of extragalactic radio sources can be used as the
indication of magnetic field directions in the spiral tangential regions, and
can be used as probes for the magnetic fields in the regions farther away than
pulsars when their median RMs are compared with pulsar RMs.
