The utility model relates to a sewage treatment settling cask technical field is a horizontal sewage treatment bidirectional flow swash plate settling cask, and it includes horizontal tank, is fixed with the left side baffle and the right side baffle that divide into horizontal tank surge chamber, reverse flow room and concurrent room in horizontal tank respectively. The utility model has the advantages of reasonable and compact structure, convenient to use, its when handling oily sewage, the utility model discloses can replace current vertical swash plate to subside the buffer tank, the one side, because the utility model discloses a horizontal type structure, consequently, the utility model discloses be convenient for remove, make complete equipment's the removal activity duration shorten to the progress of follow -up operation has been guaranteed, on the other hand, because the utility model discloses treatment effect to oily sewage obtains improving, consequently, is subsiding under the same requirement of effect, the utility model discloses a small volume that subsides the buffer tank in current vertical swash plate to reduce equipment cost, practiced thrift equipment cost.