  We propose a scheme for preparation of large-scale entangled $GHZ$ states and
$W$ states with neutral Rydberg atoms. The scheme mainly depends on Rydberg
antiblockade effect, i.e., as the Rydberg-Rydberg-interaction (RRI) strength
and the detuning between the atom transition frequency and the classical laser
frequency satisfies some certain conditions, the effective Rabi oscillation
between the two ground states and the two excitation Rydberg states would be
generated. The prominent advantage is that both two-multiparticle $GHZ$ states
and two-multiparticle $W$ states can be fused in this model, especially the
success probability for fusion of $GHZ$ states can reach unit. In addition, the
imperfections induced by the spontaneous emission is also discussed through
numerical simulation.
