The invention relates to a detection method for rotor position of a permanent-magnet synchronous motor. The detection method comprises the following steps: connecting a hybrid encoder with a motor coaxially; calculating relative position of a magnetic pole by utilizing CPU high-frequency clock counting; carrying out coarse positioning by adopting absolute signals of the hybrid encoder; then carrying out fine positioning by using incremental photoelectric pulse signals; and refining the output pulses of the encoder by utilizing high-frequency clock pulses.