This study aims to explore the effects of three different types of compound essential oils on Aedes albopictus and the spatial mosquito-repellent activity of their blended and synergistic essential oil microemulsion. According to the main compound types, six common single essential oils were combined in pairs to form three groups of compound essential oils. The ‘Y’-shaped olfactometer and sealed fumigation experiments in triangular flasks were employed to assess the repellent and fumigation knockdown activities of compound essential oils against A. albopictus, and the semi-open space simulation experiment was used to evaluate the spatial mosquito-repellent activity of their blended and synergistic essential oil microemulsion. The results showed that compound essential oil C, primarily composed of terpenes, phenols, ethers, and ketones, exhibited stronger repellent effects than compound essential oil A or B, which mainly contained aldehydes or alcohols. The blended essential oil E, with higher concentrations of terpenes, phenols and ethers, demonstrated a significantly enhanced mosquito repellent effect, achieving a repellency percentage of 82.61% ± 9.70% against A. albopictus within 20 minutes, with a median knockdown time (KT₅₀) of 5.791 minutes and KT₉₅ of 10.387 minutes. The blended essential oil microemulsion, added with a certain proportion of PEG-40 hydrogenated castor oil and ethanol, had good thermal storage stability. At both high (0.2%, V/V) and low (0.04%, V/V) concentrations, the blended microemulsions showed good spatial mosquito-repellent activity in the semi-open space, with the higher concentration achieving an average repellency percentage of 78.06% within 90 minutes. Both formulations outperformed the positive control, diethyltoluamide (DEET). This study provides an important reference for the development and application of mosquito-repellent essential oils and their microemulsions for the garden fogging system.