An adjustable waist pad (2) includes first and second bands (20, 30). An abutment face (36) at a free end (28) of the first band (20) is detachably engaged with an engagement face (38) of the second band (30). Two positioning members (44, 70) are detachably engaged with the engagement faces (24, 38) at engagement ends (26, 32) of the first and second bands (20, 30), respectively. A string (90) is extended through inner ends (46, 72) of two positioning member (44, 70) in a crisscross manner. Two elastic straps (62, 85) are fixed to the positioning members (44, 70) and detachably engaged with the first and second bands (20, 30). Two fixing members (96, 98) are fixed to two ends of the string (90). A tightening force of the waist pad (2) can be increased by pulling the elastic straps (62, 85).
