An object of the present invention is to provide a motor control system comprising an R/D converter which is capable of outputting a good phase signal without being affected by the switching noise due to a PWM signal of an inverter and a motor control method. A motor control system comprising a motor 3 having a resolver 8 as a rotary sensor; an inverter 10 for driving the motor; and a control unit 11 for controlling the inverter, the control unit executing phase calculation processing based on a phase signal which is an output of the resolver converted by an R/D converter 15, calculating a voltage reference based on a current reference and a current value of the motor detected by a current sensor 12, generating a PWM signal for controlling the inverter based on the voltage reference, wherein a PWM synchronism signal 212 in synchronism with the PWM signal is generated in the control unit, and the R/D converter 15 is driven using the PWM synchronism signal.