The band structure of a GaAs/AlGaAs double quantum well was calculated via shooting method and finite element method. The energy needed for a ground-excited state transition is 43.3 meV, indicating that a 1.2 to 1.8 kV/cm electric field can cause a horizontal transfer of carriers. The designed double quantum well structure was grown by MBE. Good metal-semiconductor contact was obtained via optimizing annealing conditions. The negative resistance effect was obtained in a 1.5 kV/cm parallel electric field, which is differs from the electric field for GaAs Gunn effect. It was concluded that the mechanism for negative resistance effect is electrons transfer from high mobility layer to low mobility layer, namely real space transfer(RST).