A stool with an adjustable stool seat is composed of stool legs and the stool seat. A plurality of threaded holes are formed in the stool seat. Bolts are connected with the threaded holes through thread pairs to form bolt assemblies. By rotating the bolts, the height of a soft head relative to the stool seat can be adjusted, the sitting face in a concave-convex shape can be presented, a user can adjust the concave-convex shape according to requirement changes, and importantly, the concave-convex shape is adjusted into a shape for containing a sitting bone so that the user can be prevented frombowing during sitting; the soft head is soft in texture and can shake when slightly bearing force, the massage function is achieved, and the normal exchange of hip tissue cell substances is facilitated.