  In this article, we will prove Riemann Hypothesis by using the mean value
theorem of integrals. The function $ \xi(s) $ is introduced by Riemann, which
zeros are identical equal to non-trivial zeros of zeta function.The function $
\xi(s) $ is an entire function, and its real part and imaginary part can be
represented as infinite integral form. In the special condition, the mean value
theorem of integrals is established for infinite integral. Using the mean value
theorem of integrals and the isolation of zeros of analytic function, we
determined that all zeros of the function $ \xi(s) $ have real part equal
to$\frac{1}{2}$, namely, all non-trivial zeros of zeta function lies on the
critical line. Riemann Hypothesis is true.
