Abstract: Abstract: 【Objective】Cyclocarya paliurus, the sole species in its genus, is a highly valued tree species with multiple functions in China. Studies on the variation of the microfibril angle of the wood of Salix. Salix can provide a basis for the selection of C. paliurus genotypes in timber forests. 【Mothed】 Based on the wood cores sampled from different natural populations, geographic variation and growth ring variation in wood microfibril angle(MFA)of C. paliurus were investigated using the X-ray diffraction technique. 【Result】 Significant variation was observed among 22 C. paliurus provenances and growth rings. Mean MFA at the breast height was 15.8° for all tested provenances, ranging from 13.4° to 20.1° when the tree age was 21 years. The wood of the Sichuan Muchuan population showed the lowest MFA, while the highest MFA was observed in Guangxi Guilin. Compared with the mean value of the 22 provenances, the MFA of Sichuan Muchuan decreased by 15.2%, but increased by 27.2% for Guangxi Guilin vs CK. The MFA of C. paliurus is affected by both latitude and longitude, and the geographic variation decreased on both sides, that is the East and West of the central longitude, 112° E, but increased on both sides, that is, the South and North of the central latitude, 29° N. MFA at breast height significantly varied among the growth rings, with a consistent pith-to-bark trend of declining angles. The relationship between MFA and growth ring could be best described by an exponential function. 【Conclusion】 Our results indicated that the MFA was relatively stable after 15 years, suggesting that there exists a great opportunity to improve wood quality of C. paliurus through selection of trees with low MFA.