Through discussion and analysis of the geochemical characteristics of C re taceous volcanic rocks in south Jiangxi and north Guangdong,it is concluded th at volcanic rocks are formed in a transitional tectonic environment (between the highl y compressed and the highly extended). Basic volcanic rocks occur in a rela tively extensional environment.The magma comes from the depth with a depleted m antle nature.Acid volc anic rocks are formed in the relatively compressed environment.The magma comes f rom the shall ow parts and is dominatedby crustal compositions.Together they constitu te the intermediate magmatic complex formation.