We propose a fast algorithm for computing Jones polynomials of Montesinos links. The Jones polynomial is a useful invariant and Montesinos links are one of the fundamental classes in knot theory. Given the Tait graph of a Montesinos diagram with $n$ edges, our algorithm runs with $\mathcal{O}(n)$ additions and multiplications in polynomials of degree $\mathcal{O}(n)$, namely in $\mathcal{O}(n^2\log n)$ time.