Abstract: In order to study the influence of special cavity structure on the pressure drop of multiple combined filter rods, 13 kinds of cavity combined filter rods of different structure were prepared. The factors including cross-sectional area ratio, cross-sectional shape, length and length proportion of cavity base rod were investigated. Data analysis was conducted with the deviation rate of pressure drop(DRPD)of cavity combined filter rods. The results showed that:1)When the cross-sectional shape of the cavity base rods was the same, the cross-sectional area ratio of the cavity base rod positively correlated to the DRPD of cavity combined filter rods of the same series. 2)At the same cross-sectional area ratio of the cavity base rod, the cross-sectional shape of the cavity base rod slightly affected the DRPD of the combined filter rod of the same series. 3)At the same cavity structure length, the length proportion of the cavity section positively correlated to the DRPD of the combined filter rod. 4) At the same length proportion of cavity section, the length of the cavity base rod negatively correlated to the DRPD of the combined filter rod. On the basis of experimental results, the factors influencing the DRPD of cavity combined filter rod were discussed. The multiple linear regression equations between special cavity structure factors and the DRPD of combined filter rod were fitted, which explained 92.0% of the variations in the dependent variables.