[en] The reproducible Lower Hybrid Wave (LHW) ion heating in the HL-1 M tokamak has been successfully carried out at plasma densities higher than 4 x 10¹³ cm^-3. A model, based on the ion Landau damping, is proposed to explain the experimental results. It has been taken into account that the electrical field, perpendicular to the toroidal magnetic field, of wave in plasma is much higher than the parallel one. Along with the assumption of n// upshifting of launched LHW spectrum, the switchover density obtained is in good agreement with experimental results of LHW ion heating performed in HL-1M as well as other tokamaks. The computational results reveal that the switchover density is very sensitive to the ratio of T_c to T_i