The brood mouse is a small mouse, with a body length of 5~8 cm and a weight of about 8 g. It is smaller than the house mouse. The ear shell is short and round, and it is only halfway between the eyes and the ear when pulled forward. With triangular ear flaps, the ear canal can be closed. The tail is slender, mostly close to or longer than the body, with 4 pairs of nipples, 2 pairs of thorax and 2 pairs of abdomen.

The brood mouse has a narrow skull, a raised skull, a thin zygomatic arch, and a small zygomatic arch Mus musculus is narrow, the nasal bone is shorter than that of Mus musculus, the posterior border of the nasal bone cannot reach the line connecting the posterior border of the premaxilla, there is no supraorbital ridge and temporal ridge, the joint suture of the parietal bone and the interparietal bone of the brood mouse is straight in the middle, and the brood mouse The two sides form two obtuse angles and the suture between the parietal and interparietal bones of Mus musculus is not straight and forms an acute angle.