In this article,the solubility,size of inhibition zone and minimum inhibitory concentration( MIC) were used as the evaluation index to study the preparation and antifungal activity of natamycin-SPI protein complex. The conditions were set as follows: natamycin concentration was 0. 5%,natamycin∶ SPI = 4∶ 1,pH = 11. 5,reaction time was 2 hours,reaction temperature was 40 ℃. The results showed that solubility of natamycin was increased by 16 times,the size of inhibition zone of natamycin-SPI protein complex was increased significantly,and the minimum inhibitory concentration to Saccharomyces cerevisiae Hansen,Penicitlium s. p,Rhizopus,Aspergilla spare were 2 mg / L,2 mg / L,4 mg / L and 2 mg / L respectively,which were half of the natamycin monomer's MIC.