Abstract: Sample preparation is the basic stage in clay experiment.The traditional method is limited to those loose-structured samples,thus unfit for samples with diagenesis.A synchronous picking-up method is used in sample preparation and analysis of 42 pieces of Mesozoic mudstone and sandstone from the Kuche Sag of the Tarim Basin.Samples are separated into 4 sections: 20 μm,20-5 μm,5-2 μm and 2 μm with parameters calculated.The results are well proved by laser analysis.