Abstract: In order to investigate the effects of ecreteur specification on tobacco density and manufacturing quality of slim cigarettes, a design method for the pocket depth of the ecreteur was established by analyzing the formation process of tobacco carpet and the function of the three-pocket ecreteur in the ZJ17 filter cigarette maker. Based on the relationship between the weight of trimmed tobacco carpet and the weight of tobacco filled in the segmented tobacco rod (regardless of the cutting loss), calculation models for the height of the tobacco carpet and the bottom area and depth of the pocket were developed separately. By analyzing the variation of segmented tobacco density, hardness and percentage of loose end rejected during the manufacturing process, the theoretical tobacco density of each segment was calculated, and the optimal pocket depth of a six-pocket ecreteur was designed. The developed models were tested on "Hao Mao" slim cigarettes in Baoji Cigarette Factory, the results showed that the optimal pocket depths for the six-pocket ecreteur were 2.6 and 0.9 mm with an arc length of 18 mm and a pocket width of 3.5 mm. After the optimization of the ecreteur, the consistency of both tobacco density and dynamic draw resistance distribution of slim cigarettes was improved, the average value of hot collapse and the number of rejected cigarettes due to loose ends on machine were reduced. This method provides support for the rapid optimization of ecreteur design.