Let
[a_1(x),a_2(x),\ldots ,a_n(x),\ldots ] be the continued fraction expansion of
x\in [0,1) and
q_n(x) be the denominator of its nth convergent. The irrationality exponent and Khintchine exponent of x are respectively defined by
\begin{align*} \overline{v}(x)=2+\limsup_{n\to\infty}\frac{\log a_{n+1}(x)}{\log q_n(x)} \quad \text{and}\quad \gamma(x)=\lim_{n\to\infty}\frac{1}{n}\sum_{i=1}^{n}\log a_i(x). \end{align*}
We study the multifractal spectrum of the irrationality exponent and the Khintchine exponent for continued fractions with nondecreasing partial quotients. For any
v>2, we completely determine the Hausdorff dimensions of the sets
\{x\in [0,1): a_1(x)\leq a_2(x)\leq \cdots , \overline {v}(x)=v\} and
\begin{align*}\bigg\{x\in[0,1): a_1(x)\leq a_2(x)\leq\cdots, \lim\limits_{n\to\infty}\frac{\log a_1(x)+\log a_2(x)+\cdots+\log a_n(x)}{\psi(n)}=1\bigg\},\end{align*}
where
\psi :\mathbb {N}\rightarrow \mathbb {R}^+ is a function satisfying
\psi (n)\to \infty as
n\to \infty .