In this section, the variations of the COVID-19 in Guangdong province are simulated and predicted based on our SEIRQ model only considering the input population from the other provinces of China (excluding Hubei province). The simulated period are from Jan 27, 2019 to Feb 19, 2020. The parameter values and the initial values of our simulation and prediction are provided in Table 1 . The performance is evaluated by the data from Feb 20, 2020 to Feb 23, 2020, and R  *  2, AE, RE, RMSE, MPAE and DISO are employed to quantify the accuracy. The simulation and prediction results are displayed in Table 2 and Fig. 2 . Table 1 Parameter estimates for COVID-19 in Guangdong province. Parameter Definitions Esimated value Source β Transmission incidence rate 2.45 × 10−8 Estimated σ The fraction of transmission incidence rate for exposed individuals 0.63 Estimated α Disease-induced death rate 0.00375 Estimated ν Transmission rate of exposed individuals to the infected class 0.183 [Zhao et al., 2020a], [Zhao et al., 2020b] γ(t) Recovery rate 0.008+0.19(1+e5.0126−0.1846t) Estimated q1(t) Quarantined rate of susceptible individuals 0.28 Estimated q2(t) Quarantined rate of exposed individuals 0.76 Estimated q3 Quarantined rate of infected individuals 0.89 Estimated A(t) Input number 86926 data B1 Output number 21356 data p1 The fraction of input population into susceptible class 0.9999927 Computed p2 The fraction of input population into exposed class 0.0000073 Computed p3 The fraction of input population into infected class 0 Assumed Initial values Definitions Esimated value Source N(0) Initial total population 113460000 GSY S(0) Initial susceptible population 113346174 Estimated E(0) Initial exposed population 31 Estimated I(0) Initial infected population 19 Estimated Sq(0) Initial quarantined susceptible population 113460 Estimated Eq(0) Initial quarantined exposed population 128 data Iq(0) Initial quarantined infected population 184 data R(0 Initial recovered population 4 data Note: GSY: Guangdong Statistical Yearbook, 2019. Table 2 Evaluation results of the simulation and prediction in Guangdong province. Different cases Simulation Prediction R * 2 AE MAPE (%) DISO 20/2 21/2 22/2 23/2 RE (%) RE (%) RE (%) RE (%) Cumulative confirmed cases 0.9973 −5.33 2.54 0.06 −0.38 −0.45 −0.37 −0.37 Confirmed cases 0.9898 −2.63 3.86 0.11 2.68 1.51 0.81 7.07 Recovered cases 0.9934 −3.38 43.32 0.17 −2.09 −1.38 −3.75 −10.41 Figure 2 Simulation and prediction of the COVID-19 in Guangdong province. (A) cumulative confirmed cases; (B) daily new confirmed cases and (C) difference of increased confirmed cases. The initial values and parameters are S(0) = 113346174, E(0) = 31, I(0) = 19, R(0) = 4, Sq(0) = 113460, Eq(0) = 128, Iq(0) = 184, A = 86926, B = 21356, p1 = 0.9999927, p2 = 0.0000073, p3 = 0, q1 = 0.28, q2 = 0.76, q3 = 0.89, α = 0.00375, β = 2.45 × 10−8, ν = 0.183, σ = 0.63, γ(t) = 0.008 + 0.19/(1 + e5.0126−0.1846t).