In order to investigate the effect of pretreatment of chitosan biological compounds on seeds of soybean (Glycine max L. cv. Williams) under salt stress conditions, a factorial experiment was conducted, adopting a completely randomized design with three replications at Shahed University in 2015. Factors examined included the combination of chitosan at three levels (0, 0.25 and 0.5 the weight-volume) and salinity at 4 levels (0, 5, 5.7 and 10 dS/m). The results showed that the interaction of chitosan and salinity had a significant impact on seed germination characteristics such as germination percentage, germination rate, mean germination time, normal seedling and physiological characteristics such as proline and soluble sugars of shoots. In contrast to salt stress increase of 30%, and an increase of 24 and 35% of proline and soluble sugars of the shoot, pretreatment of chitosan (0.25%) improves seedling germination characteristics of soybeans. Given the impact of the treatments of chitosan on seed germination and seedling growth of soybean, it is possible to introduce 0.25% W/V chitosan as a treatment to deal with conditions of salinity.