Large variations in volume and weight are characteristics of less-than-truckload freight transport. The capacity-to-weight ratio-based vehicle loading optimization can increase both the vehicle loading rate and the volume utilization rate at the same time, which can significantly reduce logistics costs. It also has important scientific research value in the transportation and logistics industries. Firstly, the capacity-weight ratio-aware mathematical model was described for the vehicle loading optimization problem. Then the algorithms used to cope with the problem was went over. At present, the majority of solution algorithms concentrate on intelligent optimization algorithms, exact and heuristic algorithms. With the development of artificial intelligence, the application of machine learning ideas in relevant aspects can also be considered. Finally, it proposes several directions to be considered in future research on the optimization problem in the current situation and expects to provide a reference for the research on the optimization of vehicle loading considering the capacity ratio.