Cyclic code is an interesting topic in coding theory and communication systems. In this paper, two families of optimal ternary cyclic codes with parameters $[3^m-1,3^m-2m-1,4]$ are presented. The first family of cyclic codes with two zeros $\pi$ and $\pi^v$ is constructed by using multivariate method. The second family of cyclic codes with two zeros $\pi^2$ and $\pi^v$ is obtained by analyzing irreducible factors of certain polynomials with finite degrees over the finite field $\mathbb{F}_{3^m}$, where $\pi$ is a generator of $\mathbb{F}_{3^m}^*$.