  A model with interlayer pairing is proposed to explain the sinusoidal
modulation of the resonant neutron scattering in high temperature
superconductors. It is found that the interlayer pairing has s-wave symmetry in
the CuO$_2$ plane and has comparable magnitude with the d-wave intralayer
pairing. It is also found that the interlayer pairing mainly affects momentum
close to the hot spots on the Fermi surface while its effect on the gap nodes
is negligible. It is pointed out that these characteristics of the interlayer
pairing can be understood in a model in which the superconducting pairing
originates from the exchange of the antiferromagnetic spin fluctuation.
