growth experiments of ammonium dihydrogen phosphate (ADP) pointseed crystal were employed. And it is shown that the growth rate of (100) surface increases linearly with the increase of supersaturation under the conditions of 0.005 kT/ωs~ 0.03 kT/ωs for phase transition drive force and 20~40 ℃ for the growth temperature. The growth rate of (100) surface increases exponentially with the rise of temperature when drive force is constant. The kinetics mechanism of crystal surface growth is in agreement with the screw dislocation growth under the condition of bulk diffusion transfer mechanism. There is death zone resulting from thermodynamic factors in crystal growth when the drive force is less than the critical value. The growth rate of (100) surface increases nonlinearly with increasing supersaturation when drive force is within 0.05 kT/ωs~0.11 kT/ωs. The crystal growth is dominated by the 2Dnucleation mechanism with the existence of other growth mechanisms.