So far, the Ngoc Lu bronze drum has been regarded as the earliest and mbst beautiful, most valuable of all the Dong Son bronze drums by the majority of domestic and foreign archaelogists or scholars. This article gives a different perspective of th.e author on the dat,e of the Ngoc Lu bronze drum. Accordingly, the earliest is the drum with half-pot-half-drum shape, temporarily called "drum X" scientifically. The drum group decorated with sketchy geometric patterns and a group of waterbirds in flight counter-clockwise in the outermost panel is considered the transitional group between "drum X" group and drum group H1 in Heger's classification, such as Ngoc Lu, Hoang Ha. Song Da, Khai Hoa, Co Loa, etc... These drums are more flawless and perfect, so they must have appeared later, dating from the 3rd - 2nd century B.C.