A slide rail kit (26, 28), comprising: a base (36, 38) comprising a base part and a connecting part (44, 56) substantially perpendicularly connected to the base part, and the connecting part (44, 56) being configured to connect the base (36, 38) to an object; a fixed rail (30, 34) arranged on the base part of the base (36, 38) and formed with a passage; and a movable rail (32, 35) configured to be movably mounted to the passage of the fixed rail (30, 34); wherein the fixed rail (30, 34) comprises a first wall, a first supporting section, a second supporting section, a second wall, a third supporting section, a fourth supporting section and a longitudinal wall, the longitudinal wall is connected between the first wall and the second wall, the first supporting section and the second supporting section are arranged on the first wall, and the third supporting section and the fourth supporting section are arranged on the second wall; wherein the passage is defined by a portion of the first wall, the first supporting section, the second supporting section, a portion of the second wall, the third supporting section and the fourth supporting section; wherein the first supporting section and the second supporting section are substantially perpendicularly connected to the first wall, and the third supporting section and the fourth supporting section are substantially perpendicularly connected to the second wall; characterized in that the base (36, 38) further comprises an extension part substantially perpendicularly connected to the connecting part (44, 56), and the base part and the extension part are extended relative to the connecting part (44, 56) respectively in a first predetermined direction and a second predetermined direction opposite to the first predetermined direction; wherein the extension part of the base (36, 38) comprises a first supporting part, and the first supporting part is configured to support the first part of the movable rail (32, 35); wherein a fitting member is connected to the extension part of the base (36, 38), the fitting member comprises a second supporting part, and the second supporting part is configured to support the second part of the movable rail (32, 35); wherein the extension part of the base (36, 38) is further arranged with an auxiliary member (78, 200) configured to support at least one of the first part, the second part and the longitudinal part of the movable rail (32, 35). a base (36, 38) comprising a base part and a connecting part (44, 56) substantially perpendicularly connected to the base part, and the connecting part (44, 56) being configured to connect the base (36, 38) to an object; a fixed rail (30, 34) arranged on the base part of the base (36, 38) and formed with a passage; and a movable rail (32, 35) configured to be movably mounted to the passage of the fixed rail (30, 34); wherein the fixed rail (30, 34) comprises a first wall, a first supporting section, a second supporting section, a second wall, a third supporting section, a fourth supporting section and a longitudinal wall, the longitudinal wall is connected between the first wall and the second wall, the first supporting section and the second supporting section are arranged on the first wall, and the third supporting section and the fourth supporting section are arranged on the second wall; wherein the passage is defined by a portion of the first wall, the first supporting section, the second supporting section, a portion of the second wall, the third supporting section and the fourth supporting section; wherein the first supporting section and the second supporting section are substantially perpendicularly connected to the first wall, and the third supporting section and the fourth supporting section are substantially perpendicularly connected to the second wall; characterized in that the base (36, 38) further comprises an extension part substantially perpendicularly connected to the connecting part (44, 56), and the base part and the extension part are extended relative to the connecting part (44, 56) respectively in a first predetermined direction and a second predetermined direction opposite to the first predetermined direction; wherein the extension part of the base (36, 38) comprises a first supporting part, and the first supporting part is configured to support the first part of the movable rail (32, 35); wherein a fitting member is connected to the extension part of the base (36, 38), the fitting member comprises a second supporting part, and the second supporting part is configured to support the second part of the movable rail (32, 35); wherein the extension part of the base (36, 38) is further arranged with an auxiliary member (78, 200) configured to support at least one of the first part, the second part and the longitudinal part of the movable rail (32, 35).