Based on Ge epitaxial layer grown on Si substrate, we have fabricated metal-semiconductor-metal (MSM) photodetectors (PD) with interdigitated graphene finger electrodes and demonstrated its opto-electrical properties. High quality Ge epitaxial layers were grown on n-type Si (100) wafers with a resistivity of 5 - 15 Ω•cm by using a rapid thermal chemical vapor deposition (RTCVD) method. The monolayer graphene grown on Cu foils using CVD method was transferred onto the cleaned Ge epilayer and was patterned by O₂ plasma reactive-ion etching (RIE) process to form interdigitated finger electrodes. From temperature dependent current-voltage (I-V) characteristics, the barrier height of graphene/Ge epilayer Schottky junction was measured to be 0.42 eV, of which value was comparable to the barrier height of graphene Schottky contact to bulk-Ge. The manufactured MSM PD with interdigitated graphene finger electrodes exhibited a considerable spectral response for wavelengths in the range of 1530 – 1560 nm, demonstrating effective photo-detection for the entire C-band (conventional band) spectrum range. On the other hand, for wavelengths > 1560 nm, its responsivity fell off rapidly, which was consistent with the Ge absorption coefficient trend. Under the illumination of incident light with a power of 3.5 mW, the maximum values of responsivity and detectivity at - 2V reverse bias were measured to be 0.35 A/W and 3.86×10¹⁰ Jones (cmHz^1/2/W) at the wavelength of 1545 nm, respectively.