By considering the interaction between Fowler-Nordheim tunneling injection theory and charge carriers transporting through the bulk, an electroluminescence model for organic single-layer diodes is presented. The expressions of the recombination current density, recombination efficiency and conductivity of the diodes are provided, which elucidate the controlling role of the electric field on mobility and recombination zone. The equilibrium of two opposite charge carriers injection and the cen-tral position of recombination zone are two important preconditions for reducing the leakage current. Space-charge-limited current occurs only over a certain high bias, meanwhile, the quantity of injection carriers increases over the transport capacity of the bulk. By considering the interaction between Fowler-Nordheim tunneling injection theory and charge carriers transporting the bulk, an electroluminescence model for organic single-layer diodes is presented. Which expressions of the recombination current density, recombination efficiency and conductivity of the diodes are provided, which elucidate the controlling role of the electric field on mobility and recombination zone. The equilibrium of two opposite charge carriers injection and the cen-tral position of recombination zone are two important preconditions for reducing the leakage current. a certain high bias, meanwhile, the quantity of injection carriers increases over the transport capacity of the bulk.