Abstract: Momordica grosvenori is a characteristic medicinal plant resource in Guangxi Zhuang Autonomous Region, and it is also one of the first batch of approved medicinal and edible plants by the Chinese government, which possesses a variety of biological activities. Its seed is the byproduct of Momordica grosvenori processing, which is rich in protein. However, during the processing, these seeds have not been treated immediately, leading to environmental pollution and greatly restricting the in-depth development of Momordica grosvenori. The utilization of these Momordica grosvenori seeds needs to be carried out urgently. In this study, the protein in defatted Momordica grosvenori seed (MSP) was prepared by the alkali-solution and acid-precipitation method. It was found that the solubility of MSP was the lowest at the pH value of 4.5, which was also the optimum pH value for precipitating protein. The effect of extraction time (0.5-2.5 h), extraction temperature (25-45 ℃), pH value (8.0-10.0) and liquid-to-solid ratio (10-20) on protein yield was investigated by single factor experiment methodology. Then, according to the variation range of single factor experiment, the response surface experiment was carried out with a total of 30 test points (including eight center points), so as to optimize the extraction process conditions. The obtained model was significant (F=131.99, P< 0.000 1) and could be used for experimental prediction, which well demonstrated the synergistic effect between various factors. Within the range of experimental factors, the optimal extraction conditions were determined as following: extraction time 2 h, extraction temperature 37 ℃, pH value 10.0 and liquid-to-solid ratio 17.5. Under the above conditions, the practical protein yield was 63.33%, close to the predicted yield. In order to further demonstrate the physicochemical properties of MSP, we systematically evaluated its functional properties. It was found that the emulsifying ability and stability of MSP were superior to those of soybean protein isolate (SPI). The foaming capacity of MSP was higher that of SPI while its foam capacity was inferior to that of SPI. The solubility, oil-holding capacity and water-holding capacity of MSP were slightly lower than those of SPI. The hardness, elasticity and cohesiveness of MSP and SPI gels were close to each other. MSP gel had a higher viscosity than SPI gel, but its adhesive viscosity, chewiness and resilience were lower than those of SPI gel. The results indicated that Momordica grosvenori seed protein is a high quality plant protein, which can be used in food industry.