Abstract: The same type of uncertainty model is usually taken into account in the existing transmission network expansion planning（TNEP） methods considering uncertainties. But in the process of TNEP, mathematical characteristic of uncertain factors may be different. In order to solve this problem, a TNEP method considering probabilistic model of renewable energy and interval model of predicted load is put forward. Firstly, an expanded stochastic chance constrained programming model considering interval number is presented. Then, a TNEP model is constructed, which considers probabilistic model and interval model of uncertainties. This model minimizs the investment cost and subjects to the expanded stochastic chance constraint of branch power. The particle swarm optimization method is employed to optimize the planning schemes and the hybrid quasi Monte Carlo simulation and improved branch-and-bound method is adopted to check the security of the given planning schemes. The case analyses on the modified IEEE RTS-24 bus system and an actual power grid verify the effectiveness and validity of the proposed planning method.