Background: Coronavirus Disease 2019 (COVID19) is currently a global public health threat. Outside of China, Italy is one of the most suffering countries with the COVID19 epidemic. It is important to predict the epidemics trend of COVID19 epidemic in Italy to help develop public health strategies. Methods: We used time series data of COVID 19 from Jan 22,2020 to Mar 16,2020. An infectious disease dynamic extended susceptible infected removed (eSIR) model, which covers the effects of different intervention measures in dissimilar periods, was applied to estimate the epidemic trend in Italy. The basic reproductive number was estimated using Markov Chain Monte Carlo methods and presented using the resulting posterior mean and 95% credible interval (CI). Hunan, with similar total number of populations in Italy, was used as a comparative item. Results: In the eSIR model, we estimated that the basic reproductive number for COVID 19 was respectively 4.10 (95% CI: 2.15 to 6.77) in Italy and 3.15(95% CI: 1.71 to 5.21) in Hunan. There would be totally 30 086 infected cases (95%CI:7920-81 869) under the current country blockade and the endpoint would be Apr 25 (95%CI: Mar 30 to Aug 07) in Italy. If the country blockade is imposed 5 day later, the total number of infected cases would expand the infection scale 1.50 times. Conclusion: Italy's current strict measures can efficaciously prevent the further spread of COVID19 and should be maintained. Necessary strict public health measures be implemented as soon as possible in other European countries with a high number of COVID19 cases. The most effective strategy needs to be confirmed in further studies.