Abstract: There is a negative-effective-mass (NEM) section in the hole energy dispersion relation for the ground subband of p-quantum-well (QW).We present a model calculation of velocity-field characteristics of holes with a NEM dispersion relation,by using nonparabolic balance-equation theory with a realistic treatment of the scatterings by hole-impurity,hole-acoustic phonon,hole-polar-optic-phonon,and hole-nonp olar-optic-phonon interactions.A "N-shaped" velocity-field relation is yielded,which is quite different from the two-valley result for electrons in bulk GaAs.An analytical expression for the "N-shaped" curve is obtained for the first time.The dependence of velocity-field relation on lattice temperature is also discussed.