Objective To understand the influence factors of the term low birth weight in western rural areas,in order to provide scientific basis for the further intervention research. Method The objects of case group were selected from mothers who delivered term low birth weight newborns in 15 county level hospitals and 8 township hospitals in 5 western counties during November 2010 to October 2011.The control group were 1∶1 matched,and the total number of qualified objects were 388 pairs.Through filling in the questionnaire by all of the objects,the general situation,maternal health care,pregnancy complications and dietary intake during pregnancy were identified. Results The risk influencing factors related to low birth weight included:the average family income <2 000 yuan per month,mother's educational degree of primary school and below,the histories of preterm birth or abnormal pregnancy,mother itself is used to be low birth weight,mother with low BMI or underweight,prenatal examination ≤4 times,oligohydramnios,preeclampsia,without folic acid intake during pregnancy,insufficient intake of fish and meat,eggs,milk,fruit,beans and nuts.Through multi-factors analysis,the average family income <2 000 yuan per month and eating nuts less than once a week during pregnancy were risk factors for term low birth weight. Conclusion At present the risk factors of low birth weight in western rural areas is mainly related to socioeconomic status and the nutritional status of pregnant women.It is necessary to enhance the quality of maternal health care services at grassroots level,in order to improve the pregnancy outcome.