A pump assembly adapted to be mounted on a container body , the pump assembly comprising a pump main body and a press rod , the press rod has a rod body and a piston portion ; the pump main body has a first cavity ; the rod body is slidably provided in the first cavity in a penetrating manner, and one end thereof extends out of the first cavity ; the piston portion is connected to the rod body and is located in the first cavity so as to divide the first cavity into a first gas cavity and a second gas cavity ;the rod body is configured to be pressed to drive the piston portion to expand the first gas cavity and compress the second gas cavity ; and the piston portion is configured to rebound under the action of the resultant force of a gas pressure in the first gas cavity and a gas pressure in the second gas cavity , so as to drive the rod body to rebound, such that the rod body is adapted to be re-pressed; the first gas cavity is a sealed cavity; the pump main body further has a gas guide channel , wherein the gas guide channel is in communication with the second gas cavity ; and a gas is discharged from or sucked into the second gas cavity through the gas guide channel ; characterized in that the pump main body comprises an outer housing and an inner housing ; the outer housing surrounds the inner housing , an inner wall of the inner housing defines the first cavity , and the piston portion is in a sliding fit with an inner wall of the inner housing ; the inner housing is provided with a first access hole , the first access hole being in communication with the first cavity ; the rod body is slidably provided in the first access hole in a penetrating manner; an outer wall of the inner housing is fitted to an inner wall of the outer housing in a surface-to-surface contact manner, wherein the inner wall of the outer housing is recessed to form the gas guide channel . the rod body is slidably provided in the first cavity in a penetrating manner, and one end thereof extends out of the first cavity ; the piston portion is connected to the rod body and is located in the first cavity so as to divide the first cavity into a first gas cavity and a second gas cavity ;the rod body is configured to be pressed to drive the piston portion to expand the first gas cavity and compress the second gas cavity ; and the piston portion is configured to rebound under the action of the resultant force of a gas pressure in the first gas cavity and a gas pressure in the second gas cavity , so as to drive the rod body to rebound, such that the rod body is adapted to be re-pressed; the first gas cavity is a sealed cavity; the pump main body further has a gas guide channel , wherein the gas guide channel is in communication with the second gas cavity ; and a gas is discharged from or sucked into the second gas cavity through the gas guide channel ; characterized in that the pump main body comprises an outer housing and an inner housing ; the outer housing surrounds the inner housing , an inner wall of the inner housing defines the first cavity , and the piston portion is in a sliding fit with an inner wall of the inner housing ; the inner housing is provided with a first access hole , the first access hole being in communication with the first cavity ; the rod body is slidably provided in the first access hole in a penetrating manner; an outer wall of the inner housing is fitted to an inner wall of the outer housing in a surface-to-surface contact manner, wherein the inner wall of the outer housing is recessed to form the gas guide channel . <EOS>