As a core wetland conservation and utilization strategy, the national wetland park considers plant color a crucial indicator for evaluating landscape quality and guiding its planning and design. This study focuses on the Nan Dianchi and Laoyuhe National Wetland Parks in Kunming, 20 typical sample plots were selected for quantitative color analysis of their plant landscapes during winter and spring. The Scenic Beauty Estimation (SBE) method was employed to establish a predictive model and identify significant influencing color factors. This research aims to provide references for designing plant landscapes in wetland parks in the southwestern region. The study reveals: (1) In winter, the landscape is predominantly characterized by orange-yellow hues (H3), which account for up to 59.91%, while in spring, it transitions to primarily yellow (H4) and yellow-green (H5), with a decrease in overall saturation and brightness. (2) The average scenic beauty score for the national wetland parks is 0.00, indicating moderate performance. The scenic beauty of winter plant landscapes generally rates higher than that of spring, with Nandianchi slightly outperforming Laoyuhe. (3) The order of significance of each color factor on scenic beauty, from most to least influential, is hue index, green ratio, brightness index, hue contrast, and color diversity. The hue and brightness indexes correlate negatively with scenic beauty, whereas hue contrast, color diversity index, and green ratio correlate positively.