Theileriosis, caused by Theileria spp., is an important tick-borne disease of small ruminants with serious impacts on animal health and livestock productivity. Although many studies have been conducted, comprehensive data on its prevalence and distribution in China remain limited. Following the PRISMA guidelines, this study systematically reviewed and analyzed 101 eligible studies published up to May 15, 2025. Literature searches were performed across six major databases: Web of Science, PubMed, ScienceDirect, Wanfang, CNKI, and VIP. Data extraction and quality assessment followed the GRADE framework, and meta-analysis was conducted in RStudio using a random-effects model. A total of 2157 records were screened, and 101 studies covering 27 provinces were included. The overall pooled prevalence of Theileria infection in small ruminants was 42.0 % (95 % CI: 33.78-54.58), with high heterogeneity among regions and climates. The highest prevalence occurred in Northwestern China (41.1 %), especially in cold semi-arid (BSk) zones (47.2 %). Among species, T. luwenshuni was most common (32.3 %), followed by T. ovis (19.8 %) and T. uilenbergi (12.5 %). Higher infection rates were recorded in goats (51.9 %) than in sheep (42.7 %), in young animals (51.1 %) than in adults, and in free-ranging systems (47.7 %) compared with more intensive management systems. A slight decline after 2015 suggested improved control efforts. This meta-analysis reveals a widespread and persistent burden of Theileria infection among small ruminants in China. T. luwenshuni and T. ovis are the dominant species, with the highest risk in Northwestern and BSk climatic regions. Strengthened region-specific surveillance, combined diagnostic approaches, and improved tick control are essential to reduce transmission and support sustainable livestock development.