We have developed a crawler-type self-propelled electric multifunctional platform to solve the problems of traditional small tractor (power < 10 kW) as followed: unreasonable selection of kinetic parameter, machinery emission, poor environmental adaptability of wheel drive, single platform function. The platform mainly consists of motor, battery box, gearbox, crawler chassis, seat, linkage, control mechanism, and PTO output. The output shaft of the motor transfers power to the input shaft of the gearbox. During working, the forward speed of the platform are adjusted by changing the gear of the gearbox, and the motor maintains a constant speed operation to keep the speed of the power take off constant and ensure the stable operation of the platform. We have designed the transmission system, power parameters and crawler mechanism. The parameters are determined as followed: the motor model of XQ-7.5-6 with the rated power of 7.5 kW and the power reserve coefficient of 20%; the transmission system includes 3 forward gears and 1 reverse gear; the crawler with the width of 230 mm, the pitch of 72 mm, and the track gauge of 650 mm. Rotary tillage and ridging test results showed that the average tillage width was 86.4 cm with the average tillage depth of 16.9 cm, and the average width of ridge top is 42.4 cm with the average width of ridge bottom being 82.7 cm and the average ridge height of 26.8 cm. The motor speed fluctuates within the range of 7% - 10% of the average speed, and the platform operates stably and the power output is even. The motor and reserve power coefficient of 20% meets the rotary farming and ridging operation requirements of small tractors.