A floorboard assembly, comprising: a plurality of floor boards, each said floor board comprising a rectangular body, said rectangular body comprising a coupling tongue longitudinally extending along one long side thereof, a coupling groove longitudinally extending along an opposite long side thereof, a first pressure block longitudinally located at a bottom side relative to said coupling tongue, a second pressure block longitudinally located at a bottom side relative to said coupling groove, a recessed portion longitudinally disposed in an outer upper side of said first pressure block adjacent to said coupling tongue, a step longitudinally extending along an outer upper side of said second pressure block adjacent to said coupling groove, and a backplane located at a bottom side thereof between said first pressure block and said second pressure block, the distance between said first pressure block and said recessed portion being equal to the distance between said second pressure block and said step, the coupling tongue of one said floor board being engageable into the coupling groove of another said floor board; and a plurality of fasteners for securing said floor boards, each said fastener comprising a base panel, a first elastic member, a second elastic member and a third elastic member, said base panel comprising a front baffle and a rear baffle respectively raised from and extended along two opposing lateral sides of a top wall thereof, a partition rib raised from the top wall and spaced between said front baffle and said rear baffle, a hooked portion curved from a top end of said partition rib in direction toward said rear baffle for selectively hooking on the step or recessed portion of one said floor board, a first accommodation open chamber defined between said front baffle and said partition rib for selectively accommodating one of the first pressure block and second pressure block of one said floor board and a second accommodation open chamber defined between said rear baffle and said partition rib for selectively accommodating one of the second pressure block and first pressure block of another said floor board, said first elastic member being attached to an inner side of said front baffle to face toward said partition rib, said second elastic member being attached to an inner side of said rear baffle to face toward said partition rib, said third elastic member being attached to one lateral side of said partition rib to face toward said front baffle. a plurality of floor boards, each said floor board comprising a rectangular body, said rectangular body comprising a coupling tongue longitudinally extending along one long side thereof, a coupling groove longitudinally extending along an opposite long side thereof, a first pressure block longitudinally located at a bottom side relative to said coupling tongue, a second pressure block longitudinally located at a bottom side relative to said coupling groove, a recessed portion longitudinally disposed in an outer upper side of said first pressure block adjacent to said coupling tongue, a step longitudinally extending along an outer upper side of said second pressure block adjacent to said coupling groove, and a backplane located at a bottom side thereof between said first pressure block and said second pressure block, the distance between said first pressure block and said recessed portion being equal to the distance between said second pressure block and said step, the coupling tongue of one said floor board being engageable into the coupling groove of another said floor board; and a plurality of fasteners for securing said floor boards, each said fastener comprising a base panel, a first elastic member, a second elastic member and a third elastic member, said base panel comprising a front baffle and a rear baffle respectively raised from and extended along two opposing lateral sides of a top wall thereof, a partition rib raised from the top wall and spaced between said front baffle and said rear baffle, a hooked portion curved from a top end of said partition rib in direction toward said rear baffle for selectively hooking on the step or recessed portion of one said floor board, a first accommodation open chamber defined between said front baffle and said partition rib for selectively accommodating one of the first pressure block and second pressure block of one said floor board and a second accommodation open chamber defined between said rear baffle and said partition rib for selectively accommodating one of the second pressure block and first pressure block of another said floor board, said first elastic member being attached to an inner side of said front baffle to face toward said partition rib, said second elastic member being attached to an inner side of said rear baffle to face toward said partition rib, said third elastic member being attached to one lateral side of said partition rib to face toward said front baffle.