Twin screw extruder was used to prepare extrusion-puffed food from Lotus seeds. The effects of material particle size and moisture content, feeding speed, extruded-cooking temperature and screw speed were studied. Through the single factor analysis, the optimal parameters of extrusion were obtained as the following: feeding speed 17～19r/min, moisture content 14%～16%, extruded-cooking temperature 155～165℃, screw speed 135～145r/min, and material particle size more than or equal to 40 mesh.