This survey was carried out to make clear the vegetation in the Vizcaino desert of Baja California peninsula in August, 1983. The vegetation of the Vizcaino desert was roughly classified into two types, oceanic and inland desert vegetation. So, in this survey, one and three survey sites were selected from oceanic and inland desert vegetation, respectively. The three survey sites of the latter located at north-mountain, central and east-south area of the Vizcaino desert. Vegetation survey in each site was mainly made by the method of summed dominance ratio used for shrub and cactus species except herb plant. Because most of herb plants had almost withered due to strict drought in summer season. Four parameters, i.e; coverage, plant density, plant height and frequency of 10 plots in each survey site were measured for calculating summed dominance ratio (SDR_4). The survey area of each plot was 100m^2 (10m×10m). Results obtained were as follows, 1. Oceanic desert vegetation was found within region which was influenced by tide from seashore. Almost all species of shrub and herb in this region were halohyte and cactus did not exist. Dominant shrub species were Encelia farinosa and Lycium andersonii. The plant species grown at seashore line which was most strictly influenced by tide were Salicornia virginica and Frankenia palmeria. 2. There were much more species of shrub and herb in inland desert vegetation compared with oceanic desert vegetation. The feature of this vegetation was appearance of cactus and decrease of halophyte. 3. Dominant species in north-mountain area were Lycium andersonii and Idria columnaris. Most of plants belonging to Cactaceae in this site were common species in central and east-south sites of the Vizcaino desert. However, Pachycormus discolor, which is a famous endemic species in this peninsula, appeared only in this area. 4. Dominant species in central part of the Vizcaino desert were Machaerocereus gummosus and Atriplex julacea. Species number of cactus in this site were fewer than those of other two inland survey sites. However, SDR_4 of Pachycereus pringlei was very high and growth as shown in height was most vigorous in this site. Fouquieria splendene, which did not appear in north-mountain survey sites existed in here. 5. Dominant species in the east-south area were Cylindropuntia inbricata and Jatropha giffordiana. In here, there was not shrub and herb species which appeared in Pacific Ocean side. SDR_4 of Prosopis glandulosa and Olneya tesota, belonging to Leguminosae were very high. Species number of cactus in this site was the heighest among the four survey sites. Especially, Lemaireocereus thurberi, which appeared in here, was an endemic species and distributed in the lower latitude of this area.