A server and a heat dissipating assembly thereof includes an airflow generating device, a central processing unit, several memory slots, a first cooling fin set, a second cooling fin set and a heat conductive member. The airflow generating device generates an airflow flowing along an airflow direction and is located at a front side of the central processing unit. The several memory slots are used to plug of memories, and they are located at a lateral side of a central processing unit. The first cooling fin set is correspondingly located over the central processing unit and at a lateral side of the memory slots. The second cooling fin set is located at a front side of the memory slots and between the airflow generating device and the memory slots. The first cooling fin set is thermally connected with the second cooling fin set via the heat conductive member.