The efficiency of a micro centrifugal pump refers to the ratio of the pump's output power to its input power, and is an important indicator for evaluating pump performance. The following are some factors that may affect the efficiency of a micro centrifugal pump:

1. Fluid properties: Fluid parameters such as viscosity, density, and temperature affect the efficiency of the pump. Generally speaking, low-viscosity, low-density fluids can improve pump efficiency, while high-viscosity, high-density fluids can reduce pump efficiency.

2. Impeller design: Impeller design is an important factor affecting pump efficiency. By optimizing parameters such as the shape, number, and angle of the impeller blades, the internal loss and friction of the pump can be reduced, and the efficiency of the pump can be improved.

3. Pump speed: Pump speed is another key factor affecting pump efficiency. Generally speaking, an appropriate speed can improve pump efficiency, but too high or too low speed will reduce pump efficiency.

4. Pump inlet and outlet pressure: Pump inlet and outlet pressure is an important factor affecting pump efficiency. Generally speaking, an appropriate inlet and outlet pressure can improve pump efficiency, but too high or too low inlet and outlet pressure will reduce pump efficiency.

5. Pump sealing performance: The pump sealing performance will also affect the pump efficiency. If the pump sealing performance is not good, it will cause leakage and backflow, reducing the pump efficiency.

6. Pump operating status: The pump operating status will also affect the pump efficiency. If the pump parts are severely worn, blocked, or malfunctioning, the pump efficiency will be reduced.

It should be noted that the above factors are not isolated, and they may affect each other, so they need to be considered and adjusted comprehensively to achieve the best pump efficiency and performance.