【正】 The nonlinear space charge effect of bunched beam in linac is one of the im-portant factors that induces the emittance growth due to the conversion of the field en-ergy to kinetic energy.In this paper,the internal field energies associated with sometransverse nonuniform space charge distributions of a bunched beam,such as Gaussiandistribution,waterbag distribution and parabolic distribution,are worked out.And theemittance growth caused by these nonuniformities are obtained.