  This study aims to investigate the systematics in planetary ephemeris
reference frames through pulsar timing observations. We used the published data
sets from several pulsar timing arrays and performed timing analyses for each
pulsar using different planetary ephemerides retrieved from the Jet Propulsion
Laboratory's Development Ephemeris (DE), Ephemeris of Planets and the Moon
(EPM), and INPOP (Int\'egration Num\'erique Plan\'etaire de l'Observatoire de
Paris). Then, we compared the timing solutions and modeled the differences in
position and proper motion by vector spherical harmonics of the first degree.
The timing solutions were also compared with those determined by very long
baseline interferometry (VLBI) astrometry. The orientation offsets between the
latest editions of the DE, EPM, and INPOP series do not exceed 0.4
milliarcseconds (mas), while the relative spins between these ephemerides are
less than 5 microarcseconds per year ($\mathrm{\mu as\,yr^{-1}}$). We do not
detect significant glides in either position or proper motion between these
ephemerides. The orientation of the pulsar timing frames deviates from that of
the VLBI frame from zero by approximately $\mathrm{0.4\,mas}$ when considering
the formal uncertainty and possible systematics. The orientation of current
planetary ephemeris frames is as accurate as at least 0.4 mas, and the
nonrotating is better than $\mathrm{5\,\mu as\,yr^{-1}}$.
