A biodegradable thrombus filter (100, 200, 11), a manufacturing method and application thereof, and a delivery device for delivering the thrombus filter (100, 200, 11), and a thrombus filter system comprising the thrombus filter (100, 200, 11) and the delivery device. The biodegradable thrombus filter (100, 200, 11) comprises a filter body (101, 201) and a center line (102, 202, 12). The filter body (101, 201) comprises a porous tubular frame (103, 203) and two porous filter mesh (104, 204) positioned at two ends of the porous tubular frame body (103, 203). The porous tubular frame (103, 203)and porous filter mesh (104, 204) are seamlessly formed via deposition of a biodegradable polymer fiber according to a pre-designed model. The center line (102, 202, 12) is manufactured using a biodegradable polymer. The center line (102, 202, 12) has one end connected to a top portion of the porous filter mesh (104, 204), passes through an internal portion of the filter (100, 200, 11) and the topportion of another porous filter mesh (104, 204), and extends outside the filter (100, 200, 11). The center line (102, 202, 12) is provided with two or more locking positions (105, 205). The center line (102, 202, 12) and the locking positions (105, 205) realize expansion of the filter (100, 200, 11) through a pulling action and allow adjustment to the size of filter expansion. The thrombus filter (100, 200, 11) has an adjustable expansion coefficient, so is less likely to be displaced, or to damage or perforate a vein during use.