A slide rail assembly, comprising: a rail member, a first bracket and at least one second bracket, the rail member being a rail member mounted on a first post and at least one second post of a rack via the first bracket and the at least one second bracket respectively, wherein the first bracket and the rail member are displaceable with respect to each other; wherein the first bracket is adjacent to an end portion of the rail member and the first bracket includes at least one first mounting member, wherein the at least one second bracket, on the other hand, is disposed on the rail member at a position away from the end portion of the rail member and includes at least one second mounting member wherein the rail member is provided with a blocking feature, and the first bracket is provided with a locking device; wherein the locking device has a locking state (S 1); wherein the blocking feature is disposed adjacent to the end portion of the rail member and is a predetermined structure, wherein the predetermined structure is one of a projection or a wall, wherein when the first bracket is at a predetermined position with respect to the rail member and the locking device is in the locking state, the locking device blocks and is blocked by the blocking feature to prevent the first bracket from being displaced from the predetermined position in a first direction, characterized in that: the locking device includes a locking member and an elastic portion, wherein the locking member stays in a certain state in response to the elastic force applied by the elastic portion to the locking member, wherein the elastic portion is one of a torsion spring, an elastic plate, and a flexible object, wherein the locking member includes an operating portion and a locking portion, with a shaft disposed between the operating portion and the locking portion to pivotally connect the locking member to the first bracket. a rail member, a first bracket and at least one second bracket, the rail member being a rail member mounted on a first post and at least one second post of a rack via the first bracket and the at least one second bracket respectively, wherein the first bracket and the rail member are displaceable with respect to each other; wherein the first bracket is adjacent to an end portion of the rail member and the first bracket includes at least one first mounting member, wherein the at least one second bracket, on the other hand, is disposed on the rail member at a position away from the end portion of the rail member and includes at least one second mounting member wherein the rail member is provided with a blocking feature, and the first bracket is provided with a locking device; wherein the locking device has a locking state (S 1); wherein the blocking feature is disposed adjacent to the end portion of the rail member and is a predetermined structure, wherein the predetermined structure is one of a projection or a wall, wherein when the first bracket is at a predetermined position with respect to the rail member and the locking device is in the locking state, the locking device blocks and is blocked by the blocking feature to prevent the first bracket from being displaced from the predetermined position in a first direction, characterized in that: the locking device includes a locking member and an elastic portion, wherein the locking member stays in a certain state in response to the elastic force applied by the elastic portion to the locking member, wherein the elastic portion is one of a torsion spring, an elastic plate, and a flexible object, wherein the locking member includes an operating portion and a locking portion, with a shaft disposed between the operating portion and the locking portion to pivotally connect the locking member to the first bracket. the locking device includes a locking member and an elastic portion, wherein the locking member stays in a certain state in response to the elastic force applied by the elastic portion to the locking member, wherein the elastic portion is one of a torsion spring, an elastic plate, and a flexible object, wherein the locking member includes an operating portion and a locking portion, with a shaft disposed between the operating portion and the locking portion to pivotally connect the locking member to the first bracket.