Background: The leukemia affects not only the quality of life (QOL) of patients with the disease but also that of their family caregivers (FCs). The research studies on QOL of FCs for leukemia patients are limited. This study aimed to evaluate the QOL of FCs for leukemia patients in Heilongjiang province, China. Methods: A cross-sectional questionnaire survey was undertaken with 309 FCs for leukemia patients recruited from three hospitals in Heilongjiang province. The QOL of the participants was assessed using the Chinese version of WHOQOL-BREF. Multivariate regression models were established to determine the predictors of the QOL of FCs, including the socio-economic characteristics of patients and FCs, and the emotional distress, social support and family functions of FCs. Results: The FCs had low QOL scores in all four domains: 12.7 ± 2.8 for physical, 12.2 ± 2.5 for psychological, 13.2 ± 2.9 for social and 11.3 ± 2.5 for environment. Social support is a major predictor of the QOL of FCs, with a standardized β coefficient of "high support" ranging from 0.41 to 0.58 for the four domains, followed by family function (β = 0.37 ~ 0.44 for psychological, social and environmental domains). The FCs who were older, highly educated, had no religious belief, suffered from a higher level of emotional distress, and provided care to younger patients and the patients without insurance coverage had lower QOL than the others. Conclusion: The study provides some important insights into the QOL of FCs for leukemia patients. The QOL of FCs for leukemia patients is low and low levels of support to FCs are a major predictor of low QOL of FCs.