The invention discloses an experimental determining method of the retention in a tobacco material roller in the processing flow, comprising the following steps of: continuously determining the real-time mass flow of materials flowing through the front part and the rear part of the roller by using electronic belt scales which are respectively arranged at the front end and the rear end of roller equipment; acquiring and recording the mass flow data determined by the electronic belt scales by a data acquisition system; continuously acquiring the mass flow information of the materials at the front end and the rear end of the roller at the material head or tail stage; meanwhile, determining the delay time that the materials are transmitted to a roller inlet from the preposed electronic belt scale and transmitted to the post-positioned electronic belt scale from a roller outlet; acquiring the mass flow information of the materials at the roller outlet according to the mass flow information of the materials at the front end and the rear end of the roller and corresponding delay time; and calculating the retention of the materials in the roller at certain moment by the data acquisition system according to the flow of the materials at the inlet and the outlet of the roller at different moments.