In this paper the whiteness intensities have been measured in the Luochuan loess profile, Shaanxi Province. Results show significant differences of whiteness intensities between loess and paleosol samples. Whiteness intensities are higher in loess than in paleosols. Based on chemical treatments and grain - size fraction, the decrease of whiteness intensities in paleosols is mainly due to the increase of concentration of fine -grained iron oxides during chemical weathering and pedogenesis. Variations of whiteness intensities in the Luochuan loess - paleosol sequence correspond well to cyclic alternation of glacial and interglacial climate. Moreover, the whiteness intensity increases gradually from bottom to top of the sequence, in accord with the general trend of global cooling indicated by evolution of oxygen isotope from deep -sea sediments. Therefore, the whiteness intensity can serve as a sensitive indicator of summer monsoon circulation and has a potential in the application to the response of global climate changes.