As it is clear that corona-virus (COVID-19) has a direct danger on the humanity in the world, at the beginning of appearing this virus till seven months later that medicine science was unable to understand the behavior of this virus, in the study we focused on the Thrombosis for 73 patients that have covid-19 as a response variable and Age, Sodium, Blood pressure as factors. We aimed to study the effect of these factors on the thrombosis for covid-19 patients, in this situation for such a response of this type Bayesian regression neural network model to predict thrombosis of the patients that have covid-19, the contribution in this study is using Bayesian regression neural network model to predict the thrombosis for the first time. Age, Sodium and Blood Pressure are capable of explaining 84% of Thrombosis. The Mse is 0.1824136 and the AIC= 14.6867 with R2 = 0.84 which is mean that age, sodium and blood pressure are able to explain 84%.