A power module assembly (1, 1a) comprising: a housing including at least one heat-dissipation surface; at least two connection sets; a circuit board comprising at least one first through hole, wherein the circuit board is mounted to the housing by the at least two connection sets; at least one resilient set (30, 30a) disposed between the housing and the circuit board, wherein the resilient set (30, 30a) comprises at least one resilient piece and each resilient piece comprises a base section and two pushing fingers, wherein the two pushing fingers are connected to each other through the base section and the two pushing fingers are outwardly extended from two opposite edges of the base section respectively, wherein bent intermediate parts of the two pushing fingers that are bent in the direction of the circuit board are pushed in the direction of the circuit board; and at least two power devices electrically connected to the circuit board and located between the resilient set and the heat-dissipation surface of the housing, wherein the two power devices are opposite to the two pushing fingers of the resilient piece respectively; wherein at least one fastening unit disposed between the two power devices and connected to the base section of the resilient piece through the first through hole, wherein the respective fastening unit passing through the first through hole is engagedly connected to the circuit board and the base section of the resilient piece, respectively, wherein each fastening unit includes a fastening part and a limiting element, the fastening part of each fastening unit being inserted into the limiting element through the associated first through hole and a third through hole in the base section and the limiting element being embedded in a first recess of the housing or a second recess of an insulation carrier (35a, 35b) forming part of the resilient set (30, 30a), such that it is movable in the axial direction of the first recess or second recess, but cannot rotate around the axial direction of the first recess or second recess respectively, such that, while the fastening part is locked into the limiting element, the limiting element is moved towards the circuit board and is engaged with the circuit board and the base section to drive the base section of the resilient piece to move toward the circuit board, so that the base section drives the intermediate parts of the two pushing fingers in the direction of the circuit board and exterior end portions, that are bent downwards in the direction of the power devices, of each pushing finger to push against a first side of the corresponding power device and so that a second side of each of the two power devices is attached to the heat-dissipation surface. a housing including at least one heat-dissipation surface; at least two connection sets; a circuit board comprising at least one first through hole, wherein the circuit board is mounted to the housing by the at least two connection sets; at least one resilient set (30, 30a) disposed between the housing and the circuit board, wherein the resilient set (30, 30a) comprises at least one resilient piece and each resilient piece comprises a base section and two pushing fingers, wherein the two pushing fingers are connected to each other through the base section and the two pushing fingers are outwardly extended from two opposite edges of the base section respectively, wherein bent intermediate parts of the two pushing fingers that are bent in the direction of the circuit board are pushed in the direction of the circuit board; and at least two power devices electrically connected to the circuit board and located between the resilient set and the heat-dissipation surface of the housing, wherein the two power devices are opposite to the two pushing fingers of the resilient piece respectively; wherein at least one fastening unit disposed between the two power devices and connected to the base section of the resilient piece through the first through hole, wherein the respective fastening unit passing through the first through hole is engagedly connected to the circuit board and the base section of the resilient piece, respectively, wherein each fastening unit includes a fastening part and a limiting element, the fastening part of each fastening unit being inserted into the limiting element through the associated first through hole and a third through hole in the base section and the limiting element being embedded in a first recess of the housing or a second recess of an insulation carrier (35a, 35b) forming part of the resilient set (30, 30a), such that it is movable in the axial direction of the first recess or second recess, but cannot rotate around the axial direction of the first recess or second recess respectively, such that, while the fastening part is locked into the limiting element, the limiting element is moved towards the circuit board and is engaged with the circuit board and the base section to drive the base section of the resilient piece to move toward the circuit board, so that the base section drives the intermediate parts of the two pushing fingers in the direction of the circuit board and exterior end portions, that are bent downwards in the direction of the power devices, of each pushing finger to push against a first side of the corresponding power device and so that a second side of each of the two power devices is attached to the heat-dissipation surface.