  We investigate the potential of the early LHC to discover the signal of
monotops, which can be decay products of some resonances in models such as
R-parity violating SUSY or SU(5), etc. We show how to constrain the parameter
space of the models by the present data of $Z$ boson hadronic decay branching
ratio, $K^0-\bar{K^0}$ mixing and dijet productions at the LHC. Then, we study
the various cuts imposed on the events, reconstructed from the hadronic final
states, to suppress backgrounds and increase the significance in detail. And we
find that in the hadronic mode the information from the missing transverse
energy and reconstructed resonance mass distributions can be used to specify
the masses of the resonance and the missing particle. Finally, we study the
sensitivities to the parameters at the LHC with $\sqrt{s}$=7 TeV and an
integrated luminosity of $1 {\rm fb}^{-1}$ in detail. Our results show that the
early LHC may detect this signal at 5$\sigma$ level for some regions of the
parameter space allowed by the current data.
