  A short gamma-ray burst GRB 090510 detected by {\it Fermi} shows an extra
spectral component between 10 MeV and 30 GeV, an addition to a more usual
low-energy ($<10$ MeV) Band component. In general, such an extra component
could originate from accelerated protons. In particular, inverse Compton
emission from secondary electron-positron pairs and proton synchrotron emission
are competitive models for reproducing the hard spectrum of the extra component
in GRB 090510. Here, using Monte Carlo simulations, we test the hadronic
scenarios against the observed properties. To reproduce the extra component
around GeV with these models, the proton injection isotropic-equivalent
luminosity is required to be larger than $10^{55}$ erg/s. Such large proton
luminosities are a challenge for the hadronic models.
