Abstract: This paper deals with the morphology of Plasmodium vivax in 60 cases observed in the northern part of Hunan Province and compares it with that observed in 6 cases from Simao Prefecture of Yunnan Province. The observations demonstrated that parasites with two or more chromatin dots and multiple invasion of erythrocytes occurred in 50.0% and 48.3% respectively. Parasites with two nuclei were much more frequently seen in younger trophozoites(5.1% ) than in older ones(1.3%), the ratio between the two being 3.9:1. This result coincided with that reported by Yang in 1982. We believed that parasites with double nuclei and the presence of multiple invasions of erythrocytes were quite common with Plasmodium vivax in certain parts of China.