Based on description of the basic geologic situation of ancient reservoir firstly discovered in Bulongguoer area of west Junggar Basin, the research of the geologic horizon and age of the ancient reservoir and preliminary analysis of the oil sources of the ancient reservoir, the authors proposed prediction mode of play of ancient reservoir formation in this paper. The geologic age of the ancient reservoir of Neopaleozoic and Bukehe Formation was identified as Famen stage of Late Devonian, and the producing pay of Mesozoic ancient reservoir was determined as Badaowan Formation of Lower Jurassic; it was inferred that the oil sources of ancient reservoir of Hebukehe Formation probably come from the generating oil and gas of continental source rocks of Shangya Member of Hujiersite Formation of Middle Devonian, and the oil sources of ancient formation of Badaowan Formation might come from the generating oil and gas of Neopaleozoic marine source rocks. The play of oil and gas of Bulongguoer area was characterized by multi-stages reservoir formation. And multi-sources, faults, uncomformities and fractures were the main passages for migration and adjustment of oil and gas. At present, Hebukehe Formation was the oldest oil-bearing series in north Xinjiang area, which had realistic guiding meanings to expand the oil and gas exploration domains of the area.