[Objective] The purpose of the article is to study the effects of nutritional components and miRNAs on the sex differentiation of Xanthoceras sorbifolium Bunge, and provide a basis for improving the sex ratio in future studies. [Methods] Non-structural carbohydrate content was measured using the anthrone colorimetric method. Mineral element content was measured via the Kjeldahl method, Mo-Sb colorimetric method, flame photometry, and atomic absorption spectrophotometry. sRNA libraries were constructed to screen differentially expressed miRNAs. Functional enrichment analysis was performed using GO and KEGG. [Results] After the appearance of internal structural differences in male and female flowers (middle stages of differentiation), the contents of soluble sugars and starch in female flowers were significantly lower than that in male flowers. The content of Mg was significantly higher in female flowers, while the content of K, Cu, and Zn was significantly lower compared to male flowers. In the late stage，the content of K, Ca, Cu, and Zn was significantly lower in female flowers, and the content of P was consistently higher in female flowers during differentiation. Fourteen miRNAs were found to affect the anabolism of starch and sugar, among which four miRNAs were differentially expressed. 17 miRNAs affect the binding transport of Fe, Mn, Cu, Ca and Mg，and 5 miRNAs are differentially expressed. [Conclusion] High levels of K, Ca, Cu and Zn are beneficial to male flower development, while high levels of soluble sugar, starch, P and Mg are beneficial to female flower development. miR408 and miR396 affect sex differentiation by influencing the above factors indirectly.