The invention provides a temperature controller for a cup. The temperature controller comprises a cover, a silica gel plug, a hollow upright column and a base, wherein a water outlet connector is arranged on the cover, the silica gel plug and the hollow upright column are located in the cover, the base covers the cover, and part of the silica gel plug is clamped in the hollow upright column and abuts against the water outlet connector; a plurality of longitudinally extending first through holes are formed in the cover, and hooked parts are arranged at the bottoms of the first through holes; an annular blocking layer is formed on the outer wall surface of the hollow upright column and divides the hollow upright column into an upper column section and a lower column section. The temperature controller for the cup can strictly control the temperature of liquid sucked out from the cup, accordingly the situation that a drinker drinks liquid which is too hot or too cold is prevented, and practicality and use safety of the cup are improved. Besides, the temperature controller for the cup is composed of the cover, the silica gel plug, the hollow upright column and the base which are connected movably, is flexible to disassemble and assemble and convenient to clean, and improves the cleanliness and use hygiene.