Spin-dependent electronic transport through a quantum dot coupled to one ferromagnetic lead and one normal metal lead is investigated by using the master equation approach.Both the intradot spin-flip transition and Coulomb interaction are studied for the current polarization p=(I_↑-I_↓)/(I_↑+I_↓).It is found that p is suppressed to zero for a particular regime of one direction bias,while it is enhanced to a relative maximum value when the bias is reversed, which is called the spin-current diode effect.The bias regime of this effect is determined by the dot level position and the intradot Coulomb interaction strength.We give a physical explanation and several control methods for it.This device is realizable with current nanofabrication technology and should have practical applications in spintronics. Spin-dependent electronic transport through a quantum dot coupled to one ferromagnetic lead and one normal metal lead is investigated by using the master equation approach. Both the intradot spin-flip transition and Coulomb interaction are studied for the current polarization p = (I_ ↑ - I_ ↓) / (I_ ↑ + I_ ↓) .It is found that p is suppressed to zero for a particular regime of one direction direction bias, while it is enhanced to a relative maximum value when the bias is reversed -current diode effect. The bias regime of this effect is determined by the dot level position and the intradot Coulomb interaction strength. We give a physical explanation and several control methods for it. This device is real with current nanofabrication technology and should have practical applications in spintronics.