Obesity, an important public health problem, is associated with the development of nonalcoholic fatty liver disease characterized by an accumulation of intrahepatic triglyceride (i.e., steatosis). Peach blossom extract mixture HT077 is the combined extracts of peach blossom (Prunus persica) and lotus leaf (Nelumbo nucifera). The objective of this study was to assess the activity of HT077 in reducing high-fat diet (HFD)-induced obesity and obesity-associated hepatic steatosis. Male C57BL/6 mice were fed either a normal diet, HFD, or HFD containing 0.2% HT077 for 10 weeks and their body weights were measured weekly. The weights of adipose tissue and liver, the hepatic levels of triglyceride and total cholesterol, and the serum levels of alanine aminotransferase (ALT) and aspartate transaminase (AST) were measured at the end of the study. The body weight of the HT077-treated HFD group was significantly lower compared with that of the HFD control group from the third week until the end of the treatment. After 10 weeks, the body weight gain and the weights of abdominal, mesenteric, and perirenal adipose tissue significantly decreased in the HT077-treated HFD group compared with those in the HFD control group. Furthermore, HT077 treatment significantly decreased the liver weight, the hepatic levels of triglyceride and total cholesterol, and the serum levels of ALT and AST compared with the HFD control group. These findings suggest that HT077 has anti-obesity effects and prevents the development of obesity-induced hepatic steatosis. HT077 may be of therapeutic value in treating obesity and nonalcoholic fatty liver disease.