The loess-paleosol sequence in the Chinese Loess Plateau provides the complete climate environment information since Quaternary. The Luochuan loess section has been the focus of paleosol sequence research as one of the standard loess sections in the central Loess Plateau. This study took the Luochuan loess section as research object. The samples came from the Potou section situated about 4km to the northern Luochuan County, whose geographic coordinate is 35°45'N and 109°25'E. We collected samples in eight layers from the Malan loess (L_1) to the S_4 paleosol of the Lishi Loess, and collected three big ring-knife samples from the upper, middle and the lower part of each loess layer respectively. Every sample had the 20 centimeters of height and 12 centimeters of diameter. The collapsibility of the loess was determined by the method of routine compression test, and the collapsibility indexes included the coefficients of collapsibility under the stress of 2kg and 3kg respectively, also self-weigh collapsibility. In the same time,the porosity and saturation of the loess were determined. According to the determination for the loess and paleosol in the Luochuan loess section, the collapsibility indexes from L_1 loess to S4 paleosol under the stress of 2kg changes between 0.002 and 0.091,the layers above layer S_2 have collapsibility, and their distribution depths are 20m. There exists strong and middle collapsibility respectively in the L_1 and L_2 loess, and their collapsibility indexes are 0. 071 and 0. 056 respectively. Also, there exists weaker and middle collapsibility respectively in the upper S_1 paleosol and the overall S_2,and their collapsibility indexes are 0. 018 and 0. 031 respectively. The L_4 loess and the above have collapsibility under the stress of 3kg,and their distribution depths arrive 28. 6m. Also, the L4 loess and the above show various degree of self-weigh collapsibility, and their distribution depths arrive 28. 6m. However, the layers under the L3 loess of the Luochuan Potou section appear no collapsibility,which showed that the unstable soil structural pores leading to loess collapsibility in such layers have been destroyed by gravity. The collapsibility indexes, porosity and saturation in the vertical depth between 0 and 20 meters of Luochuan section fluctuates with the alternation of the loess and paleosol. Collapsibility in the loess layers are stronger than in the adjacent paleosol,and the collapsibility in the S_2 paleosol experienced weak pedogenesis is stronger than that in the S_1 paleosol experienced strong pedogenesis, which were caused by different pedogenesis in the glacial period and interglacial period. The properties showed that Quaternary climate change was the main reason for the changes of collapsibility, saturation and porosity in the loess section, also showed that the research results of Quaternary climate change theory have significant value for the study on Loess engineering properties, their causes and their vertical variation law. The relationship between porosity and collapsibility coefficient followed positive correlation of exponential function. Instead, the relationship between saturation and collapsibility coefficient followed negative correlation of exponential function. Porosity and saturation have the role of indicating the strength of loess collapsibility.