Relating to the technical field of siphon filters, the invention discloses a siphon filter and a backflushing method thereof. The siphon filter includes a filtering part and a flushing part. On the basis of a traditional siphon filter, a water intake vacuum pumping pipe and a water intake vacuum breaking pipe are additionally installed on a water intake siphon, a backflushing vacuum pumping pipe and a backflushing timing tank are additionally installed on a backflushing siphon, and the use of a vacuum pump is eliminated. According to the invention, the backflushing time is fixed to reduce theconsumption of backflushing water, and the backflushing timing tank can be replaced to adjust the consumption of backflushing water so as to adapt to different use conditions; the vacuum pump is eliminated to save a lot of power; at the same time the operation steps are reduced, the operation cost is saved, and the advantages of the siphon filter can be brought into greater play, thus being more conducive to environmental protection and energy saving and more suitable for popularization and application, and producing more economic benefits.