A method for quartz rate sensor (QRS) using digital correlation detection is proposed to improve the performance of QRS. It requires a pair of orthogonal signals as input of two correlates, which can extract the in-phase and quadrature-phase component from QRS' readout signal. Then the input angular rate will be obtained from these two components. A reference channel is used to generate a pair of orthogonal signals. Phase-locked loop (PLL) and Hilbert transform can be used as the reference channel. By comparison it is concluded that the PLL has better performance than Hilbert transform.