  The LHAASO Collaboration has observed ultrahigh-energy photons up to $1.4$PeV
from $12$ $\gamma$-ray Galactic sources. In particular, the $\gamma$-ray
spectra of the sources J2226+6057, J1908+0621, J1825-1326 have been published.
We investigate the possibility of suggested origin pulsars near the sources as
the PeVatrons. The pulsar is described by a rotating magnetic dipole. Assuming
protons are uniform distributed out of the light cylinders, we obtain the
Lorentz distribution of proton energy spectrum. It is found that the protons
around pulsar could be accelerated to PeV at short times. The hadronic
$\gamma$-ray spectra of the suggested origin pulsars are in good agreement with
the LHAASO observed $\gamma$-ray spectra of the sources J2226+6057, J1908+0621,
J1825-1326.
