Abstract: Based on reservoir space and pore origin type, taking three secondary ?porosity reservoirs as examples in Junggar basin, this paper presents the concept of secondary?porosity reservoir and discusses the origins of such reservoirs in detail. It is recognized that the deposit combination dominated by dark shale and the deposited pyroclastic materials are the foundations for forming the secondary?porosity reservoirs; the zeolite and carbonate minerals generated during diagenesis are the necessary conditions; the opening of dissolution pores is the key; the trap of mature is the guarantee. The secondary?porosity reservoirs with unique formation mechanism are normally characterized by low porosity and low permeability (except for karst?vug carbonate reservoir), but the concave distribution, in?situ or nearby oil migration, source and reservoir in the same bed or in?situ reservoir, large reserves will become the new domains for oil and gas exploration in Junggar basin