A slide rail assembly , comprising: a first rail ; a second rail movable relative to the first rail , the second rail comprising an engaging feature ; and a driving mechanism comprising: a housing arranged on the first rail ; a movable member movable relative to the housing ; an actuating structure arranged on the movable member ; and an elastic member configured to provide an elastic force to the movable member ; wherein the actuating structure comprises a first part and a second part connected to the first part ; wherein the first part is configured to engage with the engaging feature of the second rail , and the second part is configured to prevent the engaging feature of the second rail from being disengaged from the first part ; wherein the housing comprises a longitudinal room , a longitudinal part , a bending part and a blocking wall , the longitudinal part is substantially parallel to the longitudinal room , the bending part is bent from the longitudinal part , the elastic member is arranged inside the longitudinal room , the movable member has a first side and a second side opposite to the first side , the first side is arranged with a first protrusion and a second protrusion , the actuating structure is arranged on the second side , the first protrusion abuts against the elastic member , the second protrusion is movable between the longitudinal part and the bending part , the blocking wall is configured to abut against the second protrusion when the movable member is located at a predetermined position, characterized by : an outline (C1) of the second part is wider than an outline (C3) of the first part . a first rail ; a second rail movable relative to the first rail , the second rail comprising an engaging feature ; and a driving mechanism comprising: a housing arranged on the first rail ; a movable member movable relative to the housing ; an actuating structure arranged on the movable member ; and an elastic member configured to provide an elastic force to the movable member ; a housing arranged on the first rail ; a movable member movable relative to the housing ; an actuating structure arranged on the movable member ; and an elastic member configured to provide an elastic force to the movable member ; wherein the actuating structure comprises a first part and a second part connected to the first part ; wherein the first part is configured to engage with the engaging feature of the second rail , and the second part is configured to prevent the engaging feature of the second rail from being disengaged from the first part ; wherein the housing comprises a longitudinal room , a longitudinal part , a bending part and a blocking wall , the longitudinal part is substantially parallel to the longitudinal room , the bending part is bent from the longitudinal part , the elastic member is arranged inside the longitudinal room , the movable member has a first side and a second side opposite to the first side , the first side is arranged with a first protrusion and a second protrusion , the actuating structure is arranged on the second side , the first protrusion abuts against the elastic member , the second protrusion is movable between the longitudinal part and the bending part , the blocking wall is configured to abut against the second protrusion when the movable member is located at a predetermined position, characterized by : an outline (C1) of the second part is wider than an outline (C3) of the first part . <EOS>