A theoretical model for calculating electric-power curves of small-size foil during its electrical explosion is given. This technique is based on temperature dependence of foil conductivity. After taking into account the energy conversion of the foil explosion, the power-time curve is applied to the hydrodynamic code. One-dimensional numerical simulations of electric-explosion driving flyers are performed using this code. Calculated flyer velocities lie within ±8% of experimental data from Lawrence Livermore National Laboratory (LLNL), and simulated history curves of flyer velocities coincide well with those measured using velocity interferometer system for any reflector (VISAR), indicating a helpful work for design optimization of slapper detonators.