Small diesel engines have weak dynamic performance and emit black smoke when working overload in a short time. With the aim to solve that problem, a kind of electric temporary turbocharger was designed. The system includes a supercharger driven by DC brushless motor, power supply system on board and a switch. The system is powered by a 24V battery and does not consume too much power due to its short running time. Bench test showed that the supercharging ratio of the electric temporary turbocharger was between 1.014 and 1.020. The power of diesel engine increased by 5.0%~9.1%. The fuel consumption decreased by 8.5%~14.0%. The smoke exhaust problem was improved. Test results indicated that the electric temporary turbocharger could meet requirement when the small diesel engines were weak dynamic performance temporarily.