The aims of this study were to detect the levels of brain neurotransmitters in mice exposed to electromagnetic irradiation produced by 3G mobile phone (3G-EMI). The mice in the growth and development period were randomly divided into three groups: the control group (C), the low-radiation group (L), and the high-radiation group (H). Group L was irradiated 30 min × 3 times per day, and group H was irradiated 60 min × 3 times per day. The contents of Acetylcholine (Ach), Dopamine (DA), and serotonin (5-HT) in the brain were then detected by liquid chromatograph-mass spectrometer (LCMS/ MS). The contents of ach in the brain neurotransmitters of experimental groups were different, but the differences were not significant (P>0.05). The content of DA in brain of high radiation group (29.170 ± 2.469 ng/g) was significantly lower than that of low radiation group (34.487 ± 2.652 ng/g) (P<0.05). The Ach contents in all the experimental groups varied, but the differences were not statistical (P>0.05). The DA content in the high-radiation group (29.170 ± 2.469 ng/g) was statistically lower than the lowradiation group (34.487 ± 2.652 ng/g) (P<0.05). The content of 5-HT in group L (1.6648 ± 0.8136 ng/g) was statistically lower than group C (3.4518 ± 0.9930 ng/g) (P<0.05), while the content of 5-HT in group H (3.9240 ± 1.2523 ng/g) was statistically higher than group L (1.6648 ± 0.8136 ng/g) (P<0.05). 3G-EMI has certain impact on the contents of brain neurotransmitters during growth and development period.