Abstract: This study aimed to investigate the processing characteristics of Chlorella proteins and their application in ice cream. Chlorella high-pressure extract was prepared using 25 kpsi cell disruption, followed by ultrafiltration (100 kDa membrane) or enzymatic hydrolysis-ethanol precipitation to obtain Chlorella purified proteins with 72% (CPP72) and 81% (CPP81) purity. Their foaming, emulsifying, and rheological properties were systematically compared with those of whey protein, and the effects of replacing skimmed milk powder with CPP72 on ice cream quality were evaluated. Results showed that CPP72 exhibited significant functional advantages: at a protein concentration of 4%, its foaming capacity (76%) and emulsifying activity index (64 m²/g) were 33% and 14% higher than those of whey protein, respectively, and its viscosity reached 52242 mPa·s (270 times that of whey protein). In ice cream applications, replacing 20% of skimmed milk powder with CPP72 enabled a 33% reduction in xanthan gum and monoglyceride usage, while maintaining core product quality. The hardness (8.3 N), overrun (69%), and sensory score (93.1 points) showed no significant difference from the control ice cream (P>0.05), and the initial drip time extended from 8 to 11 minutes. These advantages might stem from the ultrafiltration process, which not only increased protein purity but also retained certain high-molecular-weight polysaccharide components. This study demonstrates that CPP72 has excellent foam and emulsion stability, offering a promising alternative to whey protein and reducing dependency on additives in plant-based ice cream development.