The present review focuses on the properties and developing applications of carboxylated styrene butadiene rubber (XSBR) as a modified grade of styrene butadiene rubber (SBR). Carboxylated polymers, and particularly carboxylated rubbers, are regarded as a new class of polymers with superior physical and mechanical properties over non-carboxylated counterparts. Upon introducing carboxyl groups, the properties such as elasticity range, strength, compatibility towards functional fillers and polymers, resistance to hydrocarbon solvents enhance and cross-linking by non-sulfur reagents becomes possible. The XSBR latex benefits from excellent mechanical and chemical stability, excellent liquidity, high bond and conjunction strength, high toughness and the strength after molding, low water absorption and air shrinkage, excellent durability, abrasion, oil and corrosion resistance of cement products. Due to the polarity offered by carboxyl groups, fiber, and particulate composites of XSBR exhibit improved physical and mechanical properties. The stable interface created between carboxyl group and the second polymer phase generally results in an enhancement for the host polymer.