In order to analyze the measurement characteristics of microwave cigarette density distribution detector, the effects of types, width and position of tipping paper, and filling length of filter rod were studied. In this paper, the sample making method that can effectively reduce the measurement error is proposed, and the relationship model between measurement value and filling length of filter rod is also established. Our results showed that the detection accuracy can be theoretically improved by reducing the thickness of the microwave cavity, and this provides a new clue for further optimizing the detector of microwave cigarette density distribution.