The effect of spatial variation on plant community structure was studied through the comprehension to eco-geographical and climatic variables. The present study was carried out on four wadis at different elevation (Wadi Gebal at 1722-1916 m above sea level, Wadi Gharaba at 1110-1217 m a.s.l., Wadi Hodra at 600-700 m a.s.l. and Wadi Khoshbi 20-120 m a.s.l.) in Saint Katherine Protectorate, south Sinai, Egypt between March and September 2011. In this study, we used a multivariate analysis, GIS and descriptive analysis to ensure the best using and orientation for the information. As a result for the available data and analysis, we get good outputs that can help in support any conservation actions for the ecosystem. The indices of Simpson, Shannon-Weiner and Birllouin were used to estimate the floral diversity on 4 locations. Estimates showed that Wadi Gebal is the most value of diversity index (4.19) according to Shannon-Weiner Index, while the lowest value (2.7) recorded in W. Khoshbi, and the others two wadis showed, Wadi Gharaba (3.61), Wadi Hodra (3.135). The total vegetation cover over the study area was determined about 30 % of the total area studied (5000 m2). The maximum cover percentage was record in W. Gebal (38%), while the lowest value was 19% recorded in W. Gharaba. Physical and Chemical prosperities of soil showed great variation among the different elevation ranks. Results found that soil pH, and organic matter values decreased with elevation while HCO3 increased with elevation. T.D.S and EC increased with elevation without Location Wadi Hodra between 599-697m was decreased. The most stands at Wadi Gebal and Wadi Hodra finds in Northeast aspect, while most stands in Wadi Gharaba finds in NW aspect and Wadi Khoshbi in South aspect. The climatic results could explain by two words "altitudinal gradient"; because W. Gebal is the highest elevated point it received cool temperature and high rain W. Khoshbi is the lowest one in this area it receive high temperature and low rains; however, for each 1,000-foot rise in altitude there is a 4�F drop in temperature. It discerned that great variation in vegetation distribution and plant community structure, this variation may result from the variation of elevation, aspect, and slope ranks between different locations. Result for the available data was found that spatial variation play a great role in the variation of plant community structure from variation in altitudinal and latitudinal variation that leads to variation in climatic conditions and consequently, makes changes in all ecosystem components.