In this article, mechanical and compression set properties, swelling property, and stress-strain behavior during compression of polysulfide sealants based on different polysulfide resin were investigated. The results showed that molecular weight and cross-linking agent of liquid polysulfide resin had significant influence on mechanical and compression set properties of the sealants. The sealants based on higher molecular weight polysulfide resin had higher mechanical properties. At the same time, lower cross-linking agent in polysulfide resin produced lower cross-link density and higher swelling property, which resulted in higher compression set value of the sealant. However, when different molecular weight polysulfide resins were used in the sealant simultaneously, the testing results indicated that the compression performance of the sealants was significantly enhanced, while mechanical properties of the sealants kept nearly unchanged. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 1718-1723, 2010