A sampling circuit module, a memory control circuit unit, and a data sampling method, where the sampling circuit module includes a delay lock loop (DLL) and a sampling circuit. The DLL includes a clock control circuit, a clock delay circuit and a voltage control circuit. The clock control circuit performs a delay lock for a reference clock signal, so as to output a selecting signal. The clock delay circuit delays the reference clock signal according to the selecting signal, so as to output a delay clock signal. The voltage control circuit adjusts a driving voltage outputted to the clock control circuit and the clock delay circuit according to the selecting signal. The sampling circuit samples a data signal according to the delay clock signal. Accordingly, a delay ability of the DLL may be improved by adjusting the driving voltage.