The chroma and its major controlling factors of the Junwangcun loess-paleosol profile in the Hanzhong basin have been studied. The results show that the lightness is strongly linked to the organic matter. By contrast

the redness is strongly linked to the types and concentrations of iron oxides. The curves of chroma present a similar pattern to the curves of magnetic susceptibility. L*

a*

a*/b* are sensitive to climate response

which can be used as a good alternative climate index to record the changes in climate and pedogenic environment. The change of chroma indicates a cold and dry climate during the late Pleistocene (55.5~11.5 ka BP)

a climate shift from cold-dry to warm-humid during the early Holocene (between 11.5~8.5 ka BP)

a warm and humid climate during the mid-Holocene (between 8.5~3.0 ka BP)

and a cooler and drier climate during the late Holocene (since 3.0 ka BP). The climate is not persistently steady during the late Pleistocene

with a shortterm warm and wet climate in the glacial period (38.8~25.6 ka BP).