We studied the breeding ecology of the Rufous-vented Tit (Periparus rubidiventris) at Lianhuashan Nature Reserve, Gansu Province, from April to August in 2017-2018. A total of 100 nest-boxes were hung while 15 were used by Rufous-vented Tits in two years (Fig. 1). We also found four natural nests, which located in a hole of a dry birch (Betula utilize) (Fig. 1), crevice in walls and outlet pipes in cement revetment by the roadside. From mid-April, we started to check the nest-boxes once a week. When mosses or other fillings were found in the nest-boxes, we checked them more frequently (normally each day) and made notes of their laying dates, hatch dates, clutch sizes and numbers of nestlings. The data were calculated by SPSS 21.0 for Windows, and were expressed by Mean ± SE. Both sexes participated in the nest-building work. The outer part of the nest was constructed with grass stems, fibrous roots and mosses while the inner part being constructed with animal hairs and a few of small feathers. The peak of laying date was around of mid-to-late May, with one egg laid per day and an average clutch size of 6 eggs (4﹣7, n = 15). Females covered the egg with the nest materials before incubating. The average weight of the eggs was 1.12 ± 0.02 g, with the size of 15.30 ± 0.10 mm × 12.09 ± 0.11 mm (n = 86). Females began to incubate after the last egg was laid and the incubation period lasted around 15 d (14﹣16 d, n = 5). Both sexes fed the nestlings, we also measured the nestlings of 13 nests (Fig. 2). In this study, the breeding success rate was 83.3% for all nests, and 86.7% for the nest-boxes, with the main predators of mice.