This study aimed to raise the new experiment method named “umbrella deconstruction” to reveal the microscopic pore heterogeneity of tight oil sandstone reservoir by considering both the resolution and representativeness. Based on the FE-SEM and image processing technology, parameters like porosity, the ratio of the maximum to the minimum of pore orientation frequency, the content of cement, the ratio of the maximum to the minimum of cement orientation frequency and the fractal dimension of reservoir space could be applied into the microscopic heterogeneity characterization. The final imaging observation scale could reach approximately 20 mm (which is 10 times CT observation scale), the precision can reach 10 nm (almost equal to the CT observation resolution). This method would help to the research work in the microscopic heterogeneity characterization of unconventional reservoir.