Abstract: The least expected emission path with reliability in dynamic and stochastic networks was proposed. The model could ensure that travelers emitted the least emissions and arrived at the destination on time. The Lagrangian relaxation approach was employed to solve the model, and the numerical experiment for Sioux-Falls transportation network was implemented to demonstrate the efficiency of our proposed model and algorithm. The results indicate that the proposed model can achieve the least expected emission path with reliability, which provides the theoretical basis for further investigating the green travel problem.