The chemical constituents of volatiles in Acorus (A.) species, including A. gramineus, A. tatarinowii, and A. calamus, were compared by headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC/MS). The HS-SPME procedure was a more effective method in terms of the extraction yield, sample workup time, and profiling analysis than solvent extraction methods. The SPME parameters, including fiber type, extraction time and temperature, and desorption temperature and time, were optimized. The method was validated in terms of linearity, sensitivity, precision, and accuracy within the test ranges. A total of 40 volatile components were identified and tentatively characterized in three different Acorus spp. by SPME-GC/MS analysis. Chemical profiling data on twenty samples from Acorus spp. readily identified differences in volatile compositions according to geographic origins. Asarone analogues of phenylpropanoids were the predominant components, accounting for approximately 86.42% of the total volatiles in A. gramineus and 40.08% in A. tatarinowii. Sesquiterpenoids were less predominant components, accounting for about 12.34% of the total volatiles in A. gramineus and 15.98% in A. tatarinowii samples. In contrast, A. calamus samples contained oxygenated sesquiterpenoids as major components, with phenylpropanoids observed less abundantly at approximately 7.05%. The comparison of chemical profiles of Acorus spp. indicated that the composition of essential oils varied greatly with respect to geographic origins, mainly for the proportion of asarone analogues and oxygenated sesquiterpenes. In addition, principal component analysis (PCA) on the profiling data obtained by HS-SPME-GC/MS revealed a clearer classification of the geographic origins than did analysis using a solvent extraction-GC/MS method.