A thermal module includes a heat sink and a cooling fan. The heat sink has a main body, from an outer periphery thereof a plurality of radiating fins and at least one fixing section are outward extended. The fixing section is provided on one lateral side with at least one first mating part. The cooling fan has a housing having a blade hub arranged therein. The housing is provided on one side facing toward the heat sink with at least one second mating part and an axially raised wall portion. The raised wall portion is pressed against the heat sink to thereby define a space between the cooling fan and the heat sink. The cooling fan and the heat sink can be quickly assembled together through engagement of the first and the second mating part with one another to reduce the material and labor costs of the thermal module.