Objective To investigate the basic characteristics of patients with severe fever with thrombocytopenia syndrome (SFTS) and risk factors for occurrence and death of SFTS in Wendeng district, Weihai, Shandong province, China, and to provide scientific evidence for precise control and prevention of this disease. Methods A field investigation was carried out to collect the clinical and epidemiological information of the cases, and the specimens from healthy people, animals, and ticks. The virus-specific nucleic acids and antibodies were measured by quantitative real-time PCR and ELISA. The statistical differences in positive rate of antibodies between specimens of different features were determined. Results The three death cases presented with systemic symptoms including high fever, fatigue, and anorexia in the early stage, followed by consciousness disturbance and hemorrhagic manifestations in the late stage. The time interval from disease onset to death was shorter than 10 days. All the 3 cases were elderly women aged 65 years or older living in different areas of the same village, and they had no epidemiological associations. A total of 169 serum specimens from healthy people were collected. All the serum specimens were negative for IgM antibody, and 4.14% of them were positive for IgG antibody. There was a significant difference in the positive rate of IgG antibody between different age groups (χ²=6.987, P=0.030), and the positive rate of IgG antibody increased with age. Among 69 animal blood specimens, the overall positive rates of antibodies in blood specimens from sheep and dogs were 32.14% and 20.00%, respectively, while the antibodies were negative in blood specimens from raccoon dogs, chickens and cats. There was a significant difference in the positive rate of antibodies between different animals (χ²=13.263, P=0.010). The virus-specific nucleic acids were negative in all the animal blood specimens. Six ticks (one questing tick and five on-host ticks) were captured and identified as Haemaphysalis longicornis, negative for virus-specific nucleic acids. Conclusion This investigation has an important enlightenment on understanding the epidemiological characteristics of SFTS. Further research should be conducted to investigate transmission routes, pathogenic features, and risk factors for onset and death of this disease. Health promotion and education should be strengthened among the key population to raise awareness of disease prevention in key areas during high-incidence seasons.