A thorough examination of Xiaogang Lake's water quality was conducted by studying the historical monitoring data of key parameters such as concentrations of dissolved oxygen (DO), permanganate index (IMn), total nitrogen (TN), and total phosphorus (TP). The data covered the period from 2017 to 2021, enabling a comprehensive analysis of the water quality changes in Xiaogang Lake. The results revealed satisfactory levels of DO in Xiaogang Lake between 2017 and 2021, during which the annual mean concentration of IMn met the Class II evaluation standard, indicating a positive water quality status in terms of potassium permanganate index in Xiaogang Lake, Guangzhou; the annual mean of TN concentration reached Class III evaluation standard in 2017–2021; the annual mean of TP concentration reached Class III evaluation standard in 2017–2019, reached Class I evaluation standard in 2020, and reached Class II evaluation standard in 2021. The concentration of DO in Xiaogang Lake of Guangzhou exhibited significant fluctuations on a quarterly basis; the quarterly concentration of IMn reached Class II evaluation standard in 2017, 2018, and 2021; with the exception of the third quarter of 2019 and the first quarter of 2020, the quarterly IMn concentration values in all other quarters met the Class II evaluation standard; the quarterly concentrations of TN in 2017–2021 reached Class I and Class II evaluation standard less; as for the quarterly concentrations of TP, their trends varied considerably throughout the period from 2017 to 2021. An examination of the concentrations of DO, IMn, TN, and TP from 2017 to 2021 indicates variations in water quality index values, among which DO and IMn demonstrate positive trends, reflecting favorable conditions, whereas TN exhibits a deterioration in water quality.