Abstract:Objective: To find out the suitable time for collecting gallnuts. When Kaburgaia rhusicola parasailed on leaflets of Rhus potainii, the parts of the leaflets developed into gallnuts. Method: The regulation of development and tannin amount during whole growing stage were studied. Result: K. rhusicola lived in gallnuts for about 80 days. The gallnuts developed quickly during earlier stage and slowly during later stage. Gallnuts maturated from 12th, July to 30th, July, which had no relations with the size and the time for forming, but had relations with development at earlier stage. It developed quickly with earlier maturation and developed slowly with later maturation . Its tannin amount kept stable during the whole growing stage. Conclusion: The best harvesting days are those shortly after 7th, July.