The invention discloses a miRNA composition for detecting 
breast cancer brain metastases and a kit with same. The miRNA composition comprises miR-10b and one or more of miR-200a, miR-122, miR-21 and miR-181c. The kit comprises forward and reverse primers of the miRNA composition, forward and reverse primers of an 
external reference U6 
RNA, a 
cerebrospinal fluid RNA extraction 
system, a reverse transcription 
reagent, a PCR amplification 
reagent and a cDNA mixed positive 
reference product. According to the miRNA composition, a group of miRNAs are adopted as novel 
breast cancer brain metastases markers, low specificity and low sensitivity caused by 
tumor heterogeneity are hard to overcome by using a single marker can be alleviated, prognosis effectiveness evaluation of a patient suffering from 
breast cancer can be effectively improved, and thus 
clinical treatment can be instructed. The miRNA composition is used for preparing a kit or a biological 
chip for prognosis inspection on breast 
cancer by using a fluorescent quantitative / digital 
PCR method, low specificity and low sensitivity caused by 
tumor heterogeneity can be avoided, the prognosis effectiveness evaluation of the patient suffering from breast 
cancer can be effectively improved, and thus 
clinical treatment can be instructed.