Selenium (Se) is an important trace element and its deficiency has been associated with human and animal health. The human recommended dietary allowance (RDA) for adult Se intake is about 55 μg per day; however, many places in the world are lower than that level so need a dietary supply. The objective of this study was to research the effect of feed Se supplementation on Se status in milk and mozzarella cheese quality. Thirty multiparous Holstein dairy cows (3 groups) with similar condition were raised in local dairy farm. First group of dairy cow was fed with selenium yeast (0.5 mg Se/kg dry matter), second group was fed with sodium selenite at the same Se concentration, third group without Se supply as control. After 2 mo feeding, milk samples were collected for Se analysis and cheese-making. Data were analyzed by one-way ANOVA using SAS 9.3. Results showed that the Se content in milk was increased to 47.9 μg/L by selenium yeast group, significantly higher than the 25.6 μg/L in sodium selenite group when both supplied with 0.5 mg Se/kg DM. The fat, casein and whey protein of Se-milk were seperated by ultracentrifuge and the Se content was determined by atomic absorption spectroscopy. The results were 9.82%, 45.56% and 44.62% respectively. When Se-riched mozzarella cheese was made from high Se-milk and compared with control, no significant difference was found in composition or texture. But the functional properties (meltability, flowability and stretchability) were better in Se-cheese after 8 weeks storage. Additionally, the pH and a_w were lower in Se-cheese, leading to lower total plate count. The Se content increased more than 4 times in mozzarella cheese than milk, and additional Se was found in whey, hot water and brine collected during cheese-making. Organic and inorganic Se was found in Se-cheese after 8 weeks storage. Most of the Se-peptide produced during the storage was SeMet (215 ng/g) and SeCys (123 ng/g). The results of this study showed that the Se content in milk and cheese can be increased by dietary Se supplement, and the mozzarella cheese quality was not affected by feed Se supply.