A slide rail assembly, comprising: a first rail; a second rail movable relative to the first rail; a blocking member movably arranged on the first rail; wherein the first rail comprises a first wall, a second wall and a longitudinal wall connected between the first wall and the second wall of the first rail; wherein a passage is defined by the first wall, the second wall and the longitudinal wall of the first rail and configured to accommodate the second rail; wherein the second rail comprises a first wall, a second wall and a longitudinal wall connected between the first wall and the second wall of the second rail; wherein when the second rail is moved relative to the first rail from a retracted position to an extension position along a first direction, the second rail is blocked by the blocking member; wherein the first rail has an opening communicated with a first side and a second side of the longitudinal wall of the first rail, the second side being opposite to the first side; wherein the blocking member is located at a position corresponding to the opening; wherein the blocking member comprises a main body and a blocking part, said blocking part is bent from the main body; wherein the slide rail assembly further comprises an elastic member configured to provide an elastic force to the blocking member; wherein the elastic member has an elastic section located at a position corresponding to the opening; wherein the blocking member is configured to be held at a first position where the blocking part of the blocking member extends toward the first side of the longitudinal wall of the first rail, through the elastic force of the elastic member; wherein a connecting member is fixed to the first side of the longitudinal wall of the first rail, and the elastic member is arranged on the second side of the longitudinal wall of the first rail; wherein the main body of the blocking member is sandwiched between the connecting member and the elastic section of the elastic member; wherein the blocking member is configured to be held at the first position through the elastic force of the elastic section of the elastic member, the elastic force being further configured to transversely push the blocking member toward the longitudinal wall of the second rail. a first rail; a second rail movable relative to the first rail; a blocking member movably arranged on the first rail; wherein the first rail comprises a first wall, a second wall and a longitudinal wall connected between the first wall and the second wall of the first rail; wherein a passage is defined by the first wall, the second wall and the longitudinal wall of the first rail and configured to accommodate the second rail; wherein the second rail comprises a first wall, a second wall and a longitudinal wall connected between the first wall and the second wall of the second rail; wherein when the second rail is moved relative to the first rail from a retracted position to an extension position along a first direction, the second rail is blocked by the blocking member; wherein the first rail has an opening communicated with a first side and a second side of the longitudinal wall of the first rail, the second side being opposite to the first side; wherein the blocking member is located at a position corresponding to the opening; wherein the blocking member comprises a main body and a blocking part, said blocking part is bent from the main body; wherein the slide rail assembly further comprises an elastic member configured to provide an elastic force to the blocking member; wherein the elastic member has an elastic section located at a position corresponding to the opening; wherein the blocking member is configured to be held at a first position where the blocking part of the blocking member extends toward the first side of the longitudinal wall of the first rail, through the elastic force of the elastic member; wherein a connecting member is fixed to the first side of the longitudinal wall of the first rail, and the elastic member is arranged on the second side of the longitudinal wall of the first rail; wherein the main body of the blocking member is sandwiched between the connecting member and the elastic section of the elastic member; wherein the blocking member is configured to be held at the first position through the elastic force of the elastic section of the elastic member, the elastic force being further configured to transversely push the blocking member toward the longitudinal wall of the second rail.