Abstarct: Recently, Plant growth regulators apply for decrease in negative effect of different stresses. Plant resistance to biotic and abiotic stresses obtain by salicylic acid as the one of this materials. In order to survey of this subject in sugar beet an experiment was carried out in a randomized complete block design as factorial split plot with three replications in research Field of Shahrood University of Technology in 2009. The main factor was water deficit stress with three irrigation levels in 8, 12 and 16 day as non- stress, middle and severe stress respectively. The sub- factors were three concentration of salicylic acid in 0, 0.4 and 0.8 mM and times of foliar application (1 and 2 times). Storage root length increased in middle water deficit stress. but, the lowest storsge root length was related to the treatment of severe stress. Maximum and minimum storage root diameter were observed in non- stress and severe stress condition respectively. Leaf, petiol and crown dry weight and relative water content in leaf and petiol both before and after irrigation was reduced under water deficit stress. Severity of stress caused a significant reduction in leaf chlorophyll. average, 0.29 and 0.22 leaf per day was appeared in non- and severe stress treatment respectively. The effect of stress on leaf appearance rate decreased in the end of growth season. The lowest leaf death rate were obtained from non- stress conditions. foliar spray with the highest concentration of salicylic acid (0.8 mM) increased the leaf appearance rate (0.28 leaf per day). Generally, leaf death rate decreased with application of salicylic acid, but did not exist difference between salicylic acid concentrations. Death of leaves were lower in plants that had sprayed with salicylic acid in two times. Spray with the lowest levels of salicylic acid compared with control increased 2.8 and 3.7 percent in the leaf relative water content before and after irrigation respectively but doubling the concentration showed a considerable negative effect. The leaf relative water content decreased in two time foliar application.The sugar content, white sugar content and extraction coefficient of sugar increased in middle water deficit stress. Root potassium in non- stress condition was higher than stress condition. The interaction effect of stress × times on extraction coefficient of sugar were significant. The highest amount of this trait were observed in middle stress conditions × once sprayed. Most of the roots sugar molasses was obtained from combinations of treatments in non- stress × once of sprayed and severe stress × twice sprayed. Twice sprayed with 0.4 mM concentration reduced root molasses, and white sugar yield was increased. The highest root dry matter related to the combination treatments in middle stress × once sprayed. Leaf area index, Leaf area ratio and leaf weight ratio decreased in severe water deficit stress. The lowest specific leaf area to the mid- term growth period was related to severe stress conditions.