  We study the kilohertz quasi-periodic oscillations (kHz QPOs) in neutron star
low mass X-ray binaries (LMXBs) with a new magnetohydrodynamics (MHD) model, in
which the compressed magnetosphere is considered. The previous MHD model (Shi
\& Li 2009) is re-examined and the relation between the frequencies of the kHz
QPOs and the accretion rate in LMXBs is obtained. Our result agrees with the
observations of six sources (4U 0614+09, 4U 1636--53, 4U 1608--52, 4U 1915--15,
4U 1728--34, XTE 1807--294) with measured spins. In this model the kHz QPOs
originate from the MHD waves in the compressed magnetosphere. The single kHz
QPOs and twin kHz QPOs are produced in two different parts of the accretion
disk and the boundary is close to the corotation radius. The lower QPO
frequency in a frequency-accretion rate diagram is cut off at low accretion
rate and the twin kHz QPOs encounter a top ceiling at high accretion rate due
to the restriction of innermost stable circular orbit.
