Abstract: A stacked (double-layered) CdZnTe detector was fabricated experimentally by parallel method and its gamma spectrum characteristics was tested using ²⁴¹Am@59.54 keV and ⁵⁷Co@122 keV gamma ray sources. Compared with a single-layered detector, for the higher energy gamma rays of ⁵⁷Co@122 keV, the stacked CdZnTe detector exhibited higher detection efficiency and light peak efficiency, and improved the Compton continuum. The energy spectrum resolution of the stacked CdZnTe detector was slightly worse than that of the single-layered detector. The preliminary experimental results show that it is feasible to prepare a stacked CdZnTe detector by parallel method, and it can be inferred that preparation of stacked CdZnTe detectors of larger thickness will be beneficial for mid-high-energy gamma ray spectrometry.