Objective:To identify the classification characteristics and quality of life (QOL) of breast cancer (BC) patients during chemotherapy, so as to provide basis for improving the sleep and QOL of this group.Methods:A cross-sectional investigation was completed among 421 BC patients in 5 tertiary hospitals in Shanghai, Wuhan, Tangshan and Nanning in 1-12 months of 2016 using validated instruments including self-made general information questionnaire, Pittsburgh Sleep Quality Index (PSQI) and Functional Assessment of Cancer Therapy-Breast (FACT-B).Results:Four latent class of patients were identified through latent profile analysis (LPA), named by badly worse sleep quality(SQ) (C1, n=23), medium-SQ with difficulty to fall asleep (C2, n=127), medium-SQ with worse sleeping process (C3, n=30), none sleep disorders (C4, n=241). Total points of SQ among C1-C4 had significant difference ( χ2 value was 309.28, P<0.05). Age, BMI, job status, whether had surgery and course of chemotherapy between classes had statistically significant differences ( χ2 values were 9.57-25.28, all P<0.05). It had significant difference between C2 and C3, C2 and C4, C3 and C1, C3 and C4 on QOL ( χ2 values were 5.96-52.73, all P<0.05). Conclusion:SQ of BC patients during chemotherapy has heterogeneity among population. Different features of SQ of BC patients have different performance on QOL. Health professionals should keep an eye on patients with features of older age, high BMI, in job status, already received surgery and during early-stage chemotherapy, provide personal nursing intervention to improve SQ and QOL.