Mathematical model plays an important role in understanding the disease dynamics and designing strategies to control the spread of infectious diseases. In this paper, we consider a deterministic SEIS model with a saturation incidence rate and its stochastic version. To begin with, we propose the deterministic SEIS epidemic model with a saturation incidence rate and obtain a basic reproduction number
R
0
. Our investigation shows that the deterministic model has two kinds of equilibria points, that is, disease-free equilibrium
E
0
and endemic equilibrium
E
∗
. The conditions of asymptotic behaviors are determined by the two threshold parameters
R
0
and
R
0
c
. When
R
0
<
1
, the disease-free equilibrium
E
0
is locally asymptotically stable, and it is unstable when
R
0
>
1
.
E
∗
is locally asymptotically stable when
R
0
c
>
R
0
>
1
. In addition, we show that the stochastic system exists a unique positive global solution. Conditions
d
>
σ
ˇ
2
/
2
and
R
0
s
<
1
are used to show extinction of the disease in the exponent. Finally, SEIS with a stochastic version has stationary distribution and the ergodicity holds when
R
0
∗
>
1
by constructing appropriate Lyapunov function. Our theoretical finding is supported by numerical simulations. The aim of our analysis is to assist the policy-maker in prevention and control of disease for maximum effectiveness.