Abstract: Detailed assessment of the county-level biodiversity security pattern can provide scientific reference for the planning, implementation and management of regional biodiversity conservation. Taking Wengyuan County in the mountainous area of Northern Guangdong Province as an example, InVEST habitat quality model was used to achieve a comprehensive assessment of the regional biodiversity security pattern, by combining with regional topography and biodiversity characteristics and applying the habitat quality index and the composite topography and biodiversity index as evaluation indicators. The results showed that the overall habitat quality index (HQI) of Wengyuan County was good, especially in the river system and forest areas with weak anthropogenic disturbance, and the areas with low HQI were concentrated in the those strongly influenced by human activities such as construction land and cultivated land. The distribution pattern of topographic diversity composite index (TDCI) was consistent with that of relief amplitude (RA) and slope position index (SPI), but opposite to that of the relative difference of topographic wetness index (RDW). The distribution pattern of biodiversity composite index (BCI) was affected by the interaction between species diversity background in Shannon-Wiener index (H') and biodiversity richness (BR), human footprint index (HF), biodiversity significance (BS) and total vegetation coverage. The distribution of biodiversity security pattern index (BSPI) was well consistent with that of HQI, BCI and TDCI. Low-risk/low-vulnerability areas were concentrated in the county areas with strong human activities, such as urban construction land, transportation and water conservancy, and cultivated land. High-risk/high-vulnerability areas were mainly distributed in the areas with weak anthropogenic disturbances, such as nature protection and drinking water sources in the north, northwest, southeast and northeast of Wengyuan County. Through the verification and analysis of the relevant data such as the ecological protection redline, it was shown that the improved and optimized evaluation results could reflect the biodiversity security pattern of the study area more precisely and objectively.