Solar garden tractor not only drives tractor, but also does some garden works, and its driving system has unique requirement. A design method for driving system of solar garden tractor was put forward, which included the overall design and the main parameters of the theoretical calculation. Firstly, for the wheel drive mode's power transmission chain was short, and its driving and braking force distribution could be controlled and optimized by the energy management and power system, which was helpful to improve the drive system's efficiency, extend operation time and increase mileage, the wheel drive mode was therefore chosen as solar tractor drive system. Secondly, the components of solar tractor included the hub motor, the moving motor, the reducer, the battery pack and the photovoltaic panel. In order to evaluate solar tractor's working capacity, the cumulative operation time throughout day was proposed as the evaluation index. The cumulative operation time throughout day refered to the sum of solar tractor working time in a day after the battery was fully charged. According to the principle of solar tractor, i.e. obtained total energy is equal to consumed energy by the tractor, calculate the cumulative operation time throughout day. The obtained total energy by solar tractor was composed of photovoltaic panel output total energy throughout day and battery rated output energy. Based on a large number of test and analysis on solar radiation intensity and environment temperature on horizontal plane in Nanjing, solar radiation intensity model and environment temperature model were established under cloudless weather throughout the day to describe climate change. According to the parameters of photovoltaic panel, solar radiation intensity and environment temperature, the photovoltaic panel's P-V output characteristic curve was obtained, and based on the peak power of photovoltaic panel, total output energy values of 4 photovoltaic panels were calculated to be 2 976 and 1 536 W*h in summer and winter, respectively. Taking the design of solar garden tractor as an example, and combined with the Nanjing regional hourly meteorological variation, the daily generating capacity was predicted using photovoltaic panels in different seasons, and the relationships between the speed of tractor and accumulated operation time throughout day were calculated under the ramp transportation operation, ramp grass cutting operation, horizontal transportation operation and horizontal grass cutting operation working conditions. The results showed that, with the increase of operating speed, the trend of cumulative operation time throughout day was shortened, which was due to the decrease of the actual battery discharge capacity with the increase of discharge current. Under the same conditions, the cumulative operation time throughout the day in summer was longer than in winter. When the speed was 3 km/h, for tractor horizontal grass cutting operation with solar, the accumulated operation time throughout day was 14.5 h, and for without solar the time was 9.5 h. When the speed was 3 km/h, for tractor ramp grass cutting operation with solar, the accumulated operation time throughout day was 5.9 h, and under the same speed without solar, the accumulated operation time throughout day was 3.8 h. It was obvious that using photovoltaic panels greatly extended the tractor's accumulated operation time throughout day, which indicated that photovoltaic cell as garden tractor energy was feasible and also could meet the need of gardening works. The research results can be used for solar garden tractor driving system design and optimization, and provide the basis for the development of solar garden tractor.