A motor drive system,comprising: an electric motor; a drive circuit for converting an input power into a driving current (Is), wherein the driving current (Is) is provided to the electric motor to drive the electric motor; and a control unit receiving a torque command (Tn), and comprising a current command generator, wherein the current command generator contains a maximum torque per ampere (MTPA) lookup table and generates a current command according to the torque command (Tn), and the current command contains a d-axis current command (Idcom) and/or a q-axis current command (Iqcom), wherein the driving current (Is) is converted into a d-axis current (Id) and/or a q-axis current (Iq) by the control unit through coordinate conversion, and the drive circuit is controlled by the control unit, so that the driving current (Is) is close to the d-axis current command (Idcom) and/or the q-axis current command (Iqcom) corresponding to the current command, characterized in that the current command generator generates a motor operation information (ω, Tm) of the electric motor, wherein the current command generator contains a zero recycle lookup table, wherein the MTPA lookup table is a lookup table about a relationship between the torque command (Tn) and the current command according to the motor operating information when a consumed power of the electric motor is the lowest, and the zero recycle lookup table is a lookup table about a relationship between the torque command (Tn) and the current command according to the motor operating information when the consumed power of the electric motor and a recycling power of the electric motor are offset, wherein if a value of the torque command (Tn) is positive, the current command generator generates the corresponding current command according to the MTPA lookup table, wherein if the value of the torque command (Tn) is negative, the current command generator generates the corresponding current command according to the zero recycle lookup table. an electric motor; a drive circuit for converting an input power into a driving current (Is), wherein the driving current (Is) is provided to the electric motor to drive the electric motor; and a control unit receiving a torque command (Tn), and comprising a current command generator, wherein the current command generator contains a maximum torque per ampere (MTPA) lookup table and generates a current command according to the torque command (Tn), and the current command contains a d-axis current command (Idcom) and/or a q-axis current command (Iqcom), wherein the driving current (Is) is converted into a d-axis current (Id) and/or a q-axis current (Iq) by the control unit through coordinate conversion, and the drive circuit is controlled by the control unit, so that the driving current (Is) is close to the d-axis current command (Idcom) and/or the q-axis current command (Iqcom) corresponding to the current command, characterized in that the current command generator generates a motor operation information (ω, Tm) of the electric motor, wherein the current command generator contains a zero recycle lookup table, wherein the MTPA lookup table is a lookup table about a relationship between the torque command (Tn) and the current command according to the motor operating information when a consumed power of the electric motor is the lowest, and the zero recycle lookup table is a lookup table about a relationship between the torque command (Tn) and the current command according to the motor operating information when the consumed power of the electric motor and a recycling power of the electric motor are offset, wherein if a value of the torque command (Tn) is positive, the current command generator generates the corresponding current command according to the MTPA lookup table, wherein if the value of the torque command (Tn) is negative, the current command generator generates the corresponding current command according to the zero recycle lookup table.