This survey was conducted to clarify the influences of EC and pH values of the Vizcaino desert soil on vegetation, plant species number and stomatal number of leaf which relates closely to photosynthesis and transpiration. Nine sites were established for survey from seashore (Guerrero Negro) to the central part (El Vizcaino) of the Vizcaino desert. In each site, above mentioned parameters were measured in August, 1983. Results obtained were as follows, 1. EC value of soil was the highest within range of 20m from seashore line, and then it decreased in inland area. At the site of 50km from seashore, EC value became 0.2 ms/cm, which was a critical point of salinity. 2. pH value of soil was higher (pH8-9) in seashore and it decreased in inland. The pH value at 65km site was suitable for crop plants growth (pH6.5-7). 3. Plant species number of the vegetation showed increasing trend with the distance from the seashore line. There was a high significant correlation between EC value and plant species number. 4. Vegetation survey was made by summed dominance ratio (SDR_2) method based on the coverage and plant height. Dominant species of vegetation in seashore were Salicornia virginica, Frankenia palmeria, Cressa truxillensis and Mesembryanthemum crystallinum belonging to halophyte. On the other hand, in inland area, there were a lot of cactus and shrub species belonging to Xerophyte. 5. Mesembryanthemum cryastallinum which appeared in oceanic desert area and a lot of cactus which appeared in inland desert area showed the contrary distribution to EC values. That is, cactus M. crystallinum distributed in the areas of the value below 0.3ms/cm and of 0.3ms/cm -1.0ms/cm, respectively. Therefore, it is considered that both plants will become to an indicator plant for EC value. 6. There was a negative correlation between stomatal number and EC value. That is, stomatal number of herb and shrub plants increased in inland. This was due to the decrease of halophyte species in inland. Stomatal number of shrub defoliated in dry season was half or one third of not defoliated shrub. 7. Biomass of M. crystallinum in wild range area was 0.3土0.1kg/m^2in mean dry weight. However, the value at abundant grazing area (paddock) was 1.3土0.2kg/m^2. This value shows high productivity of this plant.