Abstract: Lotus seed is easy to aging during storage. To investigate the variation of the protein in aging process, lotus seeds with different storage times were as material for this study. After optimizing the protein extraction conditions by orthogonal experiment, the lotus seeds protein was obtained, and its Mr and amino acid constituents were researched by using SDS- PAGE electrophoresis and Amino Acid Automatic Analyzer, respectively. The results showed that the optimum extraction condition were p H11, solid- liquid ratio 1∶30, and extraction time 2h, the extraction rate was 60.11%. With the extension of storage time, the protein content with Mr 26 ~ 43 ku reduced gradually.The total amino acid content was highest in the fresh lotus seeds, but as the aging process, the content of methionine which is one of sulphur- containing amino acid was decreased. The lotus seeds protein changed during storage, which is one of the main reasons of aging.