The invention discloses a pipeline online filter with a function of manual sewage discharge. According to the pipeline online filter, a housing cylinder is provided with a material inlet and a material outlet, the material inlet is arranged on the lower section of the housing cylinder, the material outlet is arranged on the upper section of the housing cylinder, a filtration screen cylinder is arranged inside the housing cylinder and on the upper section inside the housing cylinder, and comprises a center shaft fixedly connected with the filtration screen cylinder body, the upper end of the center shaft penetrates through the housing cylinder, and is connected with a rotation handle, a separation plate is arranged below the filtration screen cylinder, the separation plate region positioned inside the filtration screen cylinder is provided with a plurality of small holes communicated from top to bottom, a position of the separation plate lower surface positioned below the cylinder wall of the filtration screen cylinder is connected with a sewage discharge pipe, and the sewage discharge pipe is provided with a manual valve. During operation, when filtration residues on the filtration screen cylinder are too much, the rotation handle rotates so as to rotate the filtration screen cylinder at a slow speed, the manual valve on the sewage discharge pipe is opened, a filtration process is not affected, and continuous online filtration is achieved.