To obtain the Depth Of Interaction (DOI) information for Positron Emission Tomography (PET), we proposed a novel detector design based on the light sharing technique. The detector used scintillators and silicon photomultipliers (SiPMs) with one to one coupling, employed the serpentine-light-path reflector scheme and the single-end Anger logic readout technique. Monte Carlo simulations were carried out to verify the design via GATE toolkit. An 8×1 LSO array with a crystal size of 3.1×3.1×20 mm3 was built. A flood source for generating position look-up table and five beam sources irradiating at different depths of the crystals were simulated and then calculated. The result shows that the average DOI resolution is 3.2 mm (ranging from 1 to 7 mm). In conclusion, we propose a novel detector design based on a serpentine-light-path scheme to realize DOI decoding which is a low-cost and practical direction for clinical PET systems.