Bicycle seatpost assembly with shock-absorbing functionality

A bicycle seatpost assembly, comprising:

• a seatpost unit having a hollow structure and having an opening at a top end thereof;
• a cushion adjusting unit inserted into the seatpost unit through the opening of the seatpost unit and detachably disposed at a top portion of the seatpost unit, the cushion adjusting unit comprising a fixing base, at least one positioning member, an adjustment rod, and a guide block;
• wherein the adjustment rod is disposed inside the fixing base, the at least one positioning member is abutted against an outer peripheral surface of the fixing base and an inner peripheral surface of the seatpost unit, a first side of the guide block is abutted against a bottom end of the adjustment rod, and the adjustment rod is movable relative to the fixing base so as to drive the guide block to move upwardly and downwardly;
• and
• a cushioning element abutted against a second side of the guide block of the cushion adjusting unit.