A method for detecting an occlusion in an infusion line (3) connected to an infusion device (1) comprises: measuring a force (F) applied to a piston (21) by a pusher device (12) of an infusion device (1) for moving the piston (21) along a movement direction (X) into a cylindrical tube (20) in order to deliver a medical fluid from the cylindrical tube (21) towards an infusion line (3) connected to the cylindrical tube (20)； calculating, from the measured force (F), a value indicative of a pressure (P) in the cylindrical tube (20), wherein for calculating said value indicative of said pressure (P) a frictional force value (F0) indicative of a friction of the piston (21) relative to the cylindrical tube (20) is taken into account； and comparing said value indicative of said pressure (P) to a threshold value to determine whether an occlusion is present in the infusion line (3). Herein, the frictional force value (F0) is determined using a mathematical model modelling the friction of the piston (21) relative to the cylindrical tube (20) in dependence on the position of the piston (21) relative to the cylindrical tube (20) along the movement direction (X) and in dependence on the velocity by which the piston (21) is moved relative to the cylindrical tube (3). In this way a method for reliably detecting an occlusion in an infusion line during an infusion process is provided.
