An integrated composite filter, comprising: a shell defining a chamber therein, and defining a raw water inlet, a pretreated water outlet, a pretreated water inlet, a pure water outlet and a waste water outlet which are in communication with the chamber respectively; a pretreating filtering element disposed within the chamber; a filtering membrane disposed within the chamber; and a central tube; wherein the pretreating filtering element and the filtering membrane are sequentially positioned between the raw water inlet and the pure water outlet as well as the waste water outlet, and the pretreating filtering element is positioned between the raw water inlet and the pretreated water outlet, and the filtering membrane is positioned between the pretreated water inlet and the pure water outlet as well as the waste water outlet; wherein the pretreating filtering element comprises an installation tube configured as a hollow cylinder and a filtering assembly fitted over the installation tube, a water inlet channel communicated with the raw water inlet is defined between the filtering assembly and the shell, and a pretreated water outlet channel communicated with the pretreated water outlet is defined between the filtering assembly and the installation tube; wherein the central tube is mounted within the installation tube, is spaced apart from the installation tube to define a filtering chamber communicated with the pretreated water inlet, and defines an end communicated with the pure water outlet and a water inlet hole in a sidewall of the central tube; wherein the filtering membrane is disposed within the filtering chamber and around an outer peripheral wall of the central tube, a waste water channel communicated with the waste water outlet is defined between an outer peripheral wall of the filtering membrane and an inner peripheral wall of the installation tube; and wherein the filtering assembly comprises first to third filtering layers (11, 12, 13) integrally disposed on the installation tube respectively and sequentially fitted over the installation tube from outside to inside, the first filtering layer is constituted by a polypropylene cotton, the second filtering layer is constituted by an activated carbon fiber winding layer, the third filtering layer is constituted by one of a polypropylene cotton, a microfiltration membrane and an ultrafiltration membrane, the water inlet channel communicated with the raw water inlet being defined between the first filtering layer and the shell, the pretreated water outlet channel communicated with the pretreated water outlet being defined between the third filtering layer and the installation tube. a shell defining a chamber therein, and defining a raw water inlet, a pretreated water outlet, a pretreated water inlet, a pure water outlet and a waste water outlet which are in communication with the chamber respectively; a pretreating filtering element disposed within the chamber; a filtering membrane disposed within the chamber; and a central tube; wherein the pretreating filtering element and the filtering membrane are sequentially positioned between the raw water inlet and the pure water outlet as well as the waste water outlet, and the pretreating filtering element is positioned between the raw water inlet and the pretreated water outlet, and the filtering membrane is positioned between the pretreated water inlet and the pure water outlet as well as the waste water outlet; wherein the pretreating filtering element comprises an installation tube configured as a hollow cylinder and a filtering assembly fitted over the installation tube, a water inlet channel communicated with the raw water inlet is defined between the filtering assembly and the shell, and a pretreated water outlet channel communicated with the pretreated water outlet is defined between the filtering assembly and the installation tube; wherein the central tube is mounted within the installation tube, is spaced apart from the installation tube to define a filtering chamber communicated with the pretreated water inlet, and defines an end communicated with the pure water outlet and a water inlet hole in a sidewall of the central tube; wherein the filtering membrane is disposed within the filtering chamber and around an outer peripheral wall of the central tube, a waste water channel communicated with the waste water outlet is defined between an outer peripheral wall of the filtering membrane and an inner peripheral wall of the installation tube; and wherein the filtering assembly comprises first to third filtering layers (11, 12, 13) integrally disposed on the installation tube respectively and sequentially fitted over the installation tube from outside to inside, the first filtering layer is constituted by a polypropylene cotton, the second filtering layer is constituted by an activated carbon fiber winding layer, the third filtering layer is constituted by one of a polypropylene cotton, a microfiltration membrane and an ultrafiltration membrane, the water inlet channel communicated with the raw water inlet being defined between the first filtering layer and the shell, the pretreated water outlet channel communicated with the pretreated water outlet being defined between the third filtering layer and the installation tube.