The normal range of fetal humerus length at 17 weeks of pregnancy is generally within 25 ± 5.0 mm. Humerus length refers to the length of the upper arm bone, monitoring the fetal humerus length during pregnancy is helpful to observe the development of the fetus, but due to the actual examination of the development of each fetus in the mother’s body and genetics are not the same, so the length of the humerus will be with the standard value of a certain degree of error, for the fetus at 17 weeks of gestation, the normal value of humerus length within the range of 25 ± 5.0mm. In addition, because 17 weeks of pregnancy has entered the mid-pregnancy, fetal growth and development is faster, it is recommended to strengthen the pregnancy monitoring, if the examination of the fetal humerus length and the normal value of the range is too large a difference, according to the specific circumstances of the fetus in the physician’s advice to do further examination. Pregnant women during pregnancy should pay attention to do a good job of prenatal checkups, actively listen to the advice of professional doctors to do a good job of comprehensive care and health care, pay attention to more rest, at the same time should relax, to avoid nervousness, anxiety, there is any discomfort should be timely to the hospital, by the doctor to clarify the diagnosis, and cooperate with the doctor to deal with the symptoms.