With the advancement of global maritime transport, the carriage of foreign organisms by vessels is inciting ecological catastrophes such as red tides, posing a grave threat to China’s marine environmental security. Clarifying the geographical distribution of invasive species and their relationship with climate change can provide scientific basis for their prevention and control. In this discourse, the study centers on the typical alien microalgae, Nitzschiella closterium. By integrating environmental variables and distribution data and employing an optimized Maxent model, we delve into its potential distribution in current and future ecological conditions in the coastal waters of China, as well as the response relationship to environmental variables. After model optimization, the results reveal that the Area Under the Curve (AUC) value of the training dataset for Nitzschiella closterium stands at 0.993, denoting a high degree of model accuracy and bestowing credibility upon the simulated outcomes. Currently, the high suitability area constitutes 0.74% of the total suitability area, with an area of 0.44×10⁴ km², and is mainly distributed in the sea area corresponding to Jiangsu Province, Shanghai City, and Zhejiang Province. The most significant environmental factor affecting the geographical distribution of Nitzschiella closterium is the annual temperature variation range (bio24). In the context of future climate changes, there is an overall trend of substantial expansion in the high suitability area for Nitzschiella closterium, which is profoundly affected by climate change, suggesting that the future control will be more severe. This research comprehensively understands the response relationship of the invasive species Nitzschiella closterium to leading environmental variables and its potential geographical distribution in the context of climate change through macro prediction and proposes control countermeasures. It will provide a scientific basis for preventing and controlling Nitzschiella closterium invasions.