A milk expressing device capable of simulating a babys suckling includes a first vacuum source (10), a second vacuum source (20), a throttle hole (12), a solenoid relief valve (22), a first tube (13), a second tube (23), a breast shield (30), and a control circuit board (40). The first tube (13) connecting the first vacuum source (10) and the breast shield (30) is provided with the throttle hole (12) to communicate with the atmosphere. When the first vacuum source (10) is turned off, negative pressure in the first tube (13) and the breast shield (30) disappears slowly through the throttle hole (12). The second tube (23) connecting the second vacuum source (20) and the breast shield (30) is provided with the solenoid relief valve (22) to communicate with the atmosphere. When the solenoid relief valve (22) is activated, negative pressure in the second tube (23) and in the breast shield (30) is rapidly removed. The control circuit board (40) controls the first vacuum source (10), the second vacuum source (20), and the solenoid relief valve (22).
