Three types of Cantor sets are studied. For any integer m ≥ 4, we show that every real number in [0, k] is the sum of at most k m-th powers of elements in the Cantor ternary set C for some positive integer k, and the smallest such k is 2 m . Moreover, we generalize this result to middle-1 α Cantor set for 1 < α < 2 + √ 5 and m sufficiently large. For the naturally embedded image W of the Cantor dust C × C into the complex plane C, we prove that for any integer m ≥ 3, every element in the closed unit disk in C can be written as the sum of at most 2 m+8 m-th powers of elements in W. At last, some similar results on p-adic Cantor sets are also obtained.