An electronic assembly includes a casing (10) of an electronic product, and a thermal module disposed in the casing. The casing has a sidewall (102) defining a plurality of slots (1011) therein. The thermal module includes a centrifugal blower (50), a fin assembly (40) and a plurality of sub-fins (701). The centrifugal blower defines an air outlet (502) therein. The fin assembly is disposed at the air outlet of the centrifugal blower and includes a plurality of fins (401) and has a plurality of air passages (402) formed between adjacent fins. The sub-fins are located between the fin assembly and the sidewall of the casing, and forming a plurality of air channels (702) therebetween. The air channels of the sub-fins communicate the air passages of the fin assembly with the slots of the sidewall of the casing.