A slide rail assembly, comprising: a first rail; a second rail longitudinally displaceable with respect to the first rail, wherein the second rail is provided with a working feature; a third rail longitudinally displaceable with respect to the second rail; and a switching member configured to be operated and thereby switched between a first state and a second state; wherein the second rail is displaceable with respect to the first rail to a first extended position in an opening direction, and the third rail is displaceable with respect to the first rail to a second extended position in the opening direction; wherein by switching the switching member from the first state to the second state and displacing the third rail from the second extended position to a predetermined retracted position in a retracting direction, the switching member is brought into contact with the working feature of the second rail such that the third rail is able to displace the second rail to a predetermined position in the retracting direction, with the second rail displaced simultaneously with the third rail; the slide rail assembly further comprising a first working member mounted on the third rail, wherein the first working member is switchable between a first working state and a second working state with respect to the third rail; the second rail is provided with a blocking portion; when the third rail is at the second extended position and the first working member is in the first working state, the first working member is located at one side of the blocking portion to prevent the third rail from being displaced in the opening direction with respect to the second rail at the first extended position; and once the first working member is operated and thereby switched from the first working state to the second working state, the third rail is allowed to be detached with respect to the second rail in the opening direction. characterized in that the slide rail assembly, further comprising a second working member mounted on the third rail, wherein the second working member is switchable between a first working state and a second working state with respect to the third rail; when the third rail is at the second extended position and the second working member is in the first working state, the second working member is located at an opposite side of the blocking portion to prevent the third rail from being displaced in the retracting direction with respect to the second rail at the first extended position; and when the third rail is at the second extended position and the second working member is in the second working state, the third rail is allowed to be displaced in the retracting direction with respect to the second rail at the first extended position. a first rail; a second rail longitudinally displaceable with respect to the first rail, wherein the second rail is provided with a working feature; a third rail longitudinally displaceable with respect to the second rail; and a switching member configured to be operated and thereby switched between a first state and a second state; wherein the second rail is displaceable with respect to the first rail to a first extended position in an opening direction, and the third rail is displaceable with respect to the first rail to a second extended position in the opening direction; wherein by switching the switching member from the first state to the second state and displacing the third rail from the second extended position to a predetermined retracted position in a retracting direction, the switching member is brought into contact with the working feature of the second rail such that the third rail is able to displace the second rail to a predetermined position in the retracting direction, with the second rail displaced simultaneously with the third rail; the slide rail assembly further comprising a first working member mounted on the third rail, wherein the first working member is switchable between a first working state and a second working state with respect to the third rail; the second rail is provided with a blocking portion; when the third rail is at the second extended position and the first working member is in the first working state, the first working member is located at one side of the blocking portion to prevent the third rail from being displaced in the opening direction with respect to the second rail at the first extended position; and once the first working member is operated and thereby switched from the first working state to the second working state, the third rail is allowed to be detached with respect to the second rail in the opening direction. characterized in that the slide rail assembly, further comprising a second working member mounted on the third rail, wherein the second working member is switchable between a first working state and a second working state with respect to the third rail; when the third rail is at the second extended position and the second working member is in the first working state, the second working member is located at an opposite side of the blocking portion to prevent the third rail from being displaced in the retracting direction with respect to the second rail at the first extended position; and when the third rail is at the second extended position and the second working member is in the second working state, the third rail is allowed to be displaced in the retracting direction with respect to the second rail at the first extended position.