A mixing container with a self-disengaging inner chamber and its application. The mixing container includes a container body (1), a cap (2), and a inner chamber (3) separately. It can store differentcontents within the container body (1) and the inner chamber (3) separately. The inner chamber (3) is screwed with the inner circumferential wall (12) of the cap (2) by the thread MI) to form a combination, then the combination is connected with the open part of the container body (1) by the thread (MII) on the outer circumferential wall (11) of the cap (2). Some ratchets (5) are provided on the outer wall of the inner chamber (3), and some pawls (4) are provided on the neck part of the container body (1).; When the cap (2) is screwed, the ratchets (5) are engaged with pawls (4) so as to avoidfrom rotating the inner chamber (3), and the inner chamber (3) disengages the cap (2), and drops into the container body (1), and the contents of the inner chamber (3) can mix with the contents of the container body (1) automatically, without breakage of any components of the container. The invention can mix two or more different kinds of contents in one container automatically and rapidly, and has simple structure and low cost. It can be used in the different fields widely, such as medicine, foodstuff, beverage, chemicals, pesticide and fire control equipment, etc.