Objective To evaluate the accuracy of drinks diary for the estimation of fluid intake by the elderly in nursing home. Methods The revised drinks diary (self-reported by the elderly), electronic balance weighing in the kitchen (weighed by the investigators), and 24-hour fluid intake record sheet (evaluated by nurses) were used to record the fluid intake (excluding the water in the food) of 179 nursing home elderly people within 7 days, and the fluid intake according to electronic balance weighing in the kitchen was regarded as the gold standard for comparative analysis. Results There was significant difference among the fluid intake calculated by the above three methods (P<0.01), the fluid intake estimated by drinks diary and weighed by an electronic balance were significantly more than that recorded by the sheet (P<0.01 for both). There was a positive correlation between the fluid intake estimated by drinks diary and weighed by an electronic balance (r=0.709, P<0.01). Bland-Altman plot analysis indicated that, 3.4% data were out of the 95% Confidence Interval, the fluid intake estimated by drinks diary was highly consistent with that weighed by an electronic balance. The area under ROC curve of drinks diary was 0.839, its sensitivity and specificity was 0.661 and 0.937 respectively. Conclusion Drinks diary is a simple and convenient tool for estimating fluid intake, it can improve the accuracy of fluid intake estimation for the elderly, it is conducive to monitoring fluid intake effectively and preventing low intake dehydration.