Abstract: To study the influences of puffing parameters on aerosol particle number and size from electrically heated tobacco products (eHTPs), a smoking cycle simulator-differential mobility spectrometer (SCS-DMS) was used for characterizing the particle number concentration and count median diameter (CMD) of the eHTP aerosol under different puffing parameters with the puffing volume of 35, 55, 75 mL, the puffing duration of 2, 3, 4 s, and the puffing interval of 30, 60 s respectively. The results showed that: 1) During single puff under square wave smoking regime, the particle number concentration of the aerosol from eHTP decreased and the count median diameter became smaller in real time with the proceeding of puffing. 2) The increases of puffing volume and puffing interval evidently increased particle number concentration of aerosol. When the puffing volume increased to 75 mL, the CMD of the aerosol was reduced. Puffing interval had no obvious effect on CMD. 3) Puffing durations slightly influenced the particle number concentration and CMD of the aerosol from eHTP.