Let $n_1=ef+1$ and $n_2=ef'+1$ be two distinct odd primes with positive
integers $e,\ f,\ f'.$ In this paper, the two-prime Whiteman's generalized
cyclotomic sequence of order $e=6$ is employed to construct several classes of
cyclic codes over $\mathrm{GF}(q)$ with length $n_1n_2$. The lower bounds on
the minimum distance of these cyclic codes are obtained