Complete complementary sequences are widely used in spectrum spread communications because of their ideal correlation functions. A previous method generates complete complementary sequences with lengths of $N^{n}N(n,N\in {\mathbf{Z}}^{+})$. This paper presents a new iterative method to construct complete complementary sequences with lengths of $2^{m}N(m,N\in {\mathbf{Z}}^{+})$. The analysis proves that this method can produce many sequence sets that do not appear in sequence sets generated by the former method, especially shorter sequence sets. The result will certainly increase the application of complete complementary sequences in communication engineering and related fields.