Abstract: Aiming at the problems of a single function, high cost, low efficiency, small popularization, and promotion of the vehicle-mounted pruning machinery for the central separated green belts of highway in my country, and based on the actual needs of highway greening maintenance projects, and reference of domestic and foreign hedge trimming technology, a hedge trimmer with synchronous top and side trimming was designed. This model was powered by a four-wheel tractor, whose functions included lifting the cutter, avoiding obstacles, cleaning residual branches and leaves, angle adjustment, and clutch operation. This machine could trim the central separated green belt in one round trip operation. The test showed that when the crank spindle speed was 628 r/min, the average speed of the cutter was 1.67 m/s, green belt effective trimming width was 0-1 500 mm, and trimming height was 0-1 500 mm. Additionally, the operating speed was 4-5 km/h, and the cutting frequency of the cutter was 600-650 times/min. The trimming effect was best, and the results showed that this machine meets the needs of pruning and maintenance of the central separated green belt of the expressway. It provides a new solution for further research and performance improvement of green belt pruning equipment. This machine has definite promotion value. The design also has reference significance.