This study focuses on the energy saving of construction machinery, especially excavators and wheel loaders coming on a backdrop of energy shortage and environment pollution. Due to the problem of the low energy efficiency and the pollution of conventional hydraulic excavators, hybrid hydraulic excavators were developed to solve this challenge. Firstly, this paper discusses the different configurations of the hybrid hydraulic excavator and recent research trend of hybrid hydraulic excavator is reviewed. Secondly, the productions and research of the construction machine companies were analyzed and finally, the future challenges of hybrid technology to the hydraulic excavator were discussed.