Abstract:Objective: To assay the volatile constituents of Ageratum conyzoides L. flower. Method: The volatiles were analyzed by head-space solid micro-extraction, coupled with GC/MS and Kovats. Result: There were 26 different kinds of volatile constituents in Ageratum conyzoides L. flower, 97.44% of the total essential constituents respectively. Conclusion: The major volatile constituents of Ageratum conyzoides L. flower were terpenoid.