An adjustable bed includes a bed frame supporting a plurality of platforms having at least a head platform and a back platform, a back lifting assembly, a foot lifting assembly, a base frame pivotally and detachably connected to the bed frame, a bed frame tilting actuator pivotally connected to the bed frame and the base frame for operably adjusting the bed frame from the horizontal position to the sloping position relative to the base frame, or vice versa. The adjustable bed also includes a head platform tilting actuator pivotally connected to the head platform and the back platform for operably adjusting the head platform in a tilting position or a flat position relative to the back platform.