A radiating fin assembly includes a plurality of alternately stacked first radiating fins and second radiating fins, such that a V-shaped recession is formed between any two adjacent first and second radiating fins. The V-shaped recessions are defined on at least one of two longitudinal sides of the radiating fin assembly and include a plurality of split spaces, first widened spaces, and second widened spaces. The split spaces are formed at a bottom portion of the V-shaped recessions, and the first and the second widened spaces are formed at two opposite ends of the split spaces. The radiating fin assembly can be associated with at least one heat pipe and a base to form a thermal module. With the V-shaped recessions, the radiating fin assembly and the thermal module can have widened airflow inlets, shortened airflow paths, reduced airflow pressure drop and flowing resistance, and accordingly upgraded heat dissipating efficiency.