Due to the complexity of split delivery vehicle routing problem (SDVRP), a simulation based optimization approach is proposed. A simulation model is used to capture the dynamics and uncertainties of the system and evaluate the system performance. Three split policies, LOS-policy, LDD-policy and LWT-policy are designed to implement the order split/consolidation. To optimize the route of orders in a consolidation, a genetic algorithm is developed and integrated with the simulation model. Experimental results showed that the average order size has significant impact on consolidation and split policies. Split delivery outperforms non-split delivery significantly when the average order size occupies about 60% of a truckload. Large arrival rate of orders also benefits split delivery. Sparse distribution of customers deteriorates the performance of split delivery. In various experimental scenarios, LDD-policy is always better than LOS-policy and LWT-policy.