Urban mountain parks are different from urban parks in that they form a unique microclimate environment with special topographical advantages and natural ecological environment. The study aims to investigate the thermal comfort condition and its related visitations in urban mountain parks in the hot summer and cold winter climate. Particularly, the research conducted thermal comfort measurement and visitation observation in three urban mountain parks in Mianyang City. The measurement and observation covered three months: August, October and December of 2018, which represents summer, autumn and winter respectively. The study included climate measurement, questionnaire survey and observation of the attendance rate in the selected parks. Results showed that temperature and solar radiation are the two most important factors affecting the use of parks. The neutral PET (Physiologically Equivalent Temperature) value is 27.0 °C in summer, 23.2 °C in autumn, and 17.3 °C in winter. This study can help to better plan and design outdoor environments of urban mountain parks to encourage people’s visits and social interaction.