The invention provides a cavity filter. The cavity filter comprises a main cavity and multiple sub filtering cavities formed in the main cavity, wherein the multiple sub filtering cavities are coupled and connected in series through coupling connecting sheets; and the two ends of the multiple serially-connected sub filtering cavities are connected with connectors outside the main cavity through tapping connecting sheets. Compared with the prior art, the main cavity of the cavity filter can be manufactured easily by die casting or other proximate matters, so that the period from product design to batch production can be greatly shortened, and the product cost is also lowered; the standard sub filtering cavities can be designed by a die casting die in a one-to-many manner, so that multiple standard sub filtering cavities can be obtained in one time by die casting for use or through proximate matters; the standard sub filtering cavities, used as a standard library, can be directly used in design; and in addition, the standard sub filtering cavities can be combined and arranged optionally, thereby improving the design efficiency and shortcoming the development period.