With continuous expansion of exploration activity, reservoir evaluation system, based on current reservoir characteristics, has not increasingly suited to dynamic evaluation for hydrocarbon accumulation of reservoir with low porosity and permeability. Because reservoir properties often change after hydrocarbon accumulation, lower property limit of reservoir has not objectively reflected the lower limit of the reservoir quality in the hydrocarbon accumulation period. And the application of significance for lower property limit of reservoir becomes very limited. Therefore the author proposes the new ideas that the concept of \"critical properties of reservoir\" is used for reservoir evaluation. By the combination of hydrocarbon accumulation mechanism and reservoir evaluation，hydrocarbon accumulation capacity for low porosity and permeability of the reservoir can be re-understanding. This paper proposes three determination methods of critical properties of the reservoir that are ①log data analysis, ②well testing analysis and ③experimental analysis of critical charge properties in the oil-bearing sandstone. Obviously due to the weak diagenesis after hydrocarbon accumulation, critical properties of normal reservoir, that has little changed, can be determined by the lower property limit of reservoir obtained from log data analysis and well testing analysis. But due to the greatly reducing of porosity and permeability, of reservoir, critical properties of reservoir for low porosity and permeability need be restored. The application of critical properties of reservoir is the supplement for traditional reservoir evaluation. Only being combined with hydrocarbon accumulation and dynamically evaluating reservoir quality, different hydrocarbon reservoir can be objectively distinguished. In the reservoir evaluation for low porosity and permeability, parameters analysis for critical properties of reservoir more effectively evaluate and predict reservoirs’ conditions.