Oxygen saturation as an important indicator of the state of oxygen is a significant basis to the health care workers on disease prevention，diagnosis and treatment.Due to the defects of the current pulse oximeter such as power consumption，poor stability，the balance between price and instrument accuracy，a cost-effective，low-power and wireless transmission photoelectric pulse oximeter is designed.The system used oximeter finger clip to acquire the oxygen signal and took the STM32 chip as its CPU，then the collected signal is analyzed，processed and displayed on the screen，the detection of blood oxygen saturation portable real-time continuous is realized.After repeating the experiment under different conditions by Fluck Index2 oximeter simulator，the extensive experimental results demonstrate that the accuracy is 2% when oxygen saturation is between 60% to 80% and the accuracy is 1% when oxygen saturation is between 80% to 99%，the pulse rate error is less than 1bpm.The results show that the design has reached the standard requirements for medical equipment，which makes the design has good value in use.