The development of effective hemp decortication methods has been considered as an emerging need by the bio-composites and other fiber industries. In this study, the drop weight method was used for hemp decortication. Tests were conducted using a laboratory-scale impactor (consisting of a hammer and a mold). In the tests, a 40-g sample of hemp stalk was placed in the mold where it was subjected to various impact intensities from different numbers of hammer drops. These different impact intensities corresponded to different energy inputs onto the given mass of hemp sample. The energy inputs were expressed as specific energy levels and they were 4.5, 9.1, 13.6, 18.2, 22.7, and 27.2 MJ Mg-1. Two types of hemp sample, named as hemp A (unretted hemp) and hemp B (retted hemp), were used in the tests. Two different sieving scenarios (without-sieving and with-sieving between hammer drops) were also applied in the tests. The results showed that using higher specific energy to impact hemp stalk, higher fiber yield, and fiber detaching efficiency could be achieved. Sieving the chaff (particles smaller than 20 mm) out between hammer drops could further improve the fiber yield and detaching efficiency. The best performance of the drop weight method was observed for the treatment of the hemp B with sieving at the highest specific energy level. This treatment gave a fiber yield of 24% and a detaching efficiency of 0.89.