Based on the evidence from morphology, literature survey and specimen examination, Piper curtipedunculum (Piperaceae) is recognized as independent species which is used to be a synonym of Piper pedicellatum. Piper boehmeriifolium var. glabricaule, Piper terminaliflorum and Piper yunnanense are considered as new synonyms of P. pedicellatum to which they are similar by a series of morphological characters. And the morphological differences, similarities and geographical ranges of these plant are clarified.