分辨力是传感器和测量仪器的重要技术参数。数字仪器的分辨力通常取决于内部模数转换器的位数，但如何确定由仪器和传感器组成的检测系统的分辨力，目前尚未见到与之相关的专门性研究成果。该文论证了检测系统的分辨力只与随机误差相关，要提高分辨力就必须减小测量结果的随机波动。通过实验提出了检测系统分辨力的定量计算公式，并证明了其置信概率大于90.9%。Resolution is one of the key specifications for instruments. Generally, the resolution of digitized instruments dependent on their internal Analog to Digital Converter (ADC); but few related studies are published concern with the resolution of measurement system composed of instrument and sensors. Firstly it’s argued that resolution is only related to random errors; in order to improve resolution, the random fluctuations of measured results have to be decreased. Provided with mass experimental data, a formula for quantified calculating the resolution of measurement system is then presented, and 2.35σ is recommended to be an appreciated acceptable resolution. Lastly, more than 90.9% of confidence probability is proved to be achieved by using the formula.