A slide rail assembly, comprising: a first rail comprising a first wall, a second wall and a first longitudinal wall connected between the first wall and the second wall, a passage being defined by the first wall, the second wall and the first longitudinal wall; a second rail movably mounted in the passage of the first rail; a sliding auxiliary device arranged in the passage of the first rail, the sliding auxiliary device comprising a plurality of rolling members configured to support between the first rail and the second rail; and a first function member arranged on the first rail and adjacent to an end portion of the first rail and the first wall, wherein the first function member comprises a first function portion, a second function portion, and a first connecting portion, the first function portion is located in the passage of the first rail, the second function portion exceeds the end portion of the first rail and located at outside of the passage of the first rail; the first rail comprising a second connecting portion corresponding to the first connecting portion, the first connecting portion and the second connecting portion are configured to be connected to each other; the second rail comprising at least one pushing portion (72a, 72b); wherein when the second rail is moved from a first predetermined position along a first direction and a rail section of the second rail exceeds the end portion the first rail and is located at the outside of the passage of the first rail, the second function portion of the first function member is configured to support a part of the rail section of the second rail; wherein when the second rail is moved from the first predetermined position along the first direction to a second predetermined position, the sliding auxiliary device is pushed by the at least one pushing portion (72a, 72b) of the second rail and moved from a first sliding auxiliary position to a second sliding auxiliary position and the first function portion of the first function member is able to block the sliding auxiliary device to stop at the second sliding auxiliary position, in order to prevent the sliding auxiliary device from being moved from the passage of the first rail to the outside of the passage of the first rail. a first rail comprising a first wall, a second wall and a first longitudinal wall connected between the first wall and the second wall, a passage being defined by the first wall, the second wall and the first longitudinal wall; a second rail movably mounted in the passage of the first rail; a sliding auxiliary device arranged in the passage of the first rail, the sliding auxiliary device comprising a plurality of rolling members configured to support between the first rail and the second rail; and a first function member arranged on the first rail and adjacent to an end portion of the first rail and the first wall, wherein the first function member comprises a first function portion, a second function portion, and a first connecting portion, the first function portion is located in the passage of the first rail, the second function portion exceeds the end portion of the first rail and located at outside of the passage of the first rail; the first rail comprising a second connecting portion corresponding to the first connecting portion, the first connecting portion and the second connecting portion are configured to be connected to each other; the second rail comprising at least one pushing portion (72a, 72b); wherein when the second rail is moved from a first predetermined position along a first direction and a rail section of the second rail exceeds the end portion the first rail and is located at the outside of the passage of the first rail, the second function portion of the first function member is configured to support a part of the rail section of the second rail; wherein when the second rail is moved from the first predetermined position along the first direction to a second predetermined position, the sliding auxiliary device is pushed by the at least one pushing portion (72a, 72b) of the second rail and moved from a first sliding auxiliary position to a second sliding auxiliary position and the first function portion of the first function member is able to block the sliding auxiliary device to stop at the second sliding auxiliary position, in order to prevent the sliding auxiliary device from being moved from the passage of the first rail to the outside of the passage of the first rail.