A milk powder box (12, 22, 32, 42, 52) and milk powder brewing device (10, 20, 30, 40, 50), the milk powder box (12, 22, 32, 42, 52) having a box body (125, 225, 325, 425, 525), a box bottom (123, 223, 323, 423, 523) and a second connecting mechanism (124, 224, 324, 424, 524)； the upper part of the milk powder box (12, 22, 32, 42, 52) can be connected to a nipple and can be connected to a feeding bottle (11, 21, 31, 41, 51) through the second connecting mechanism (124, 224, 324, 424, 524), and the milk powder box (12, 22, 32, 42, 52) has a milk powder outlet (126, 226, 326, 426, 526)； the box body (125, 225, 325, 425, 525) can move longitudinally relative to the feeding bottle (11, 21, 31, 41, 51) connected to the milk powder box (12, 22, 32, 42, 52), such that the milk powder box (12, 22, 32, 42, 52) is provided with a first working position and a second working position； in the first working position, the milk powder outlet (126, 226, 326, 426, 526) is closed, and the box body (125, 225, 325, 425, 525) and the box bottom (123, 223, 323, 423, 523) together form a milk powder accommodation cavity isolated from the water in the feeding bottle (11, 21, 31, 41, 51), and in the second working position, the milk powder outlet (126, 226, 326, 426, 526) is opened, and the feeding bottle (11, 21, 31, 41, 51) opens into the nipple via the milk powder box (12, 22, 32, 42, 52), forming a milk channel hermetically isolated from the outside. The milk powder brewing device (10, 20, 30, 40, 50) comprises a feeding bottle (11, 21, 31, 41, 51) and a milk powder box (12, 22, 32, 42, 52)； water and milk powder are prepared before using the milk powder brewing device (10, 20, 30, 40, 50)； when brewing, only one step is needed: making a relative movement between the box body (125, 225, 325, 425, 525) and the feeding bottle (11, 21, 31, 41, 51). By overcoming the inconvenience in the prior art of removing the milk powder box and reconnecting the nipple and the feeding bottle to brew the
