Abstract: Based on 11 MeV small medical cyclotron of Institute of Fluid Physics, Chinese Academy of Engineering Physics, a set of small volume liquid target system with silver as target cavity material was developed by ¹⁸O(p,n)¹⁸F reaction. The design process of target structure and its thermodynamic analysis results were introduced in detail in this paper. The cooling performance and the stability of the target system were tested. The analysis result shows that the target system has good stability. Under the experimental conditions, the experimental structure has good stability and high repeatability. Under the beam intensity of 30 μA, the activity stability of the products is good, with an average of 5.846×10¹⁰ Bq, and most of the yields are between 65% and 75% of the theoretical yield.