The invention discloses a filter element of a fuel oil filter. The filter element comprises cylindrical filter paper which is folded into a serrated form, an inner net, an upper cover plate and a lower cover plate, wherein the inner net is inserted into the cylindrical filter paper, and a filtering space is formed in the inner net; the upper cover plate and the lower cover plate are separately fixed to the two ends of the cylindrical filter paper, the upper cover plate is provided with a first through hole for communicating an oil outlet pipe with the filtering space, and the lower cover plateis provided with a second through hole into which a sensor is inserted; and the cylindrical filter paper is a composite layer comprising an inner layer made from wood pulp paper to which 30% of glassfibers are added, a middle layer made from a melt-blown cotton material and an outer layer made from non-woven fabric, and the inner layer is closer to the inner net than the outer layer. The strength, filtering precision and water separating efficiency of the filter element can be improved, and the dust holding quantity can be increased, so that the service life of the filter element is prolonged.