Sandstone porosity is an important factor for hydrocarbon reservoirs. Based on the analysis of statistical porosity data from ten Chinese basins, three different trendlines has been found for basins of different categories. High average porosity reservoir is often developed in the Eastern Rift Basins, occasionally in the Western Superimposed Basins. The sandstone reservoir of Middle Craton Basins is always developed with low average porosity. However, the reservoir porosity decreased with increasing depth vertically with one or two anomalously high porosity belt only in the Eastern Rift Basins. According to these results, we should take basin category as a key factor to make porosity prediction in the hydrocarbon exploration.