Abstract: Contents of amino acids (AA) in the flowers, stems and fruits of pitayagrown on saline habitats were analyzed. The results indicated that the fruit flesh, pericarps, biennial stems, annual branches, petals and filaments all contained the 17 AAs detected. The total AA content (fresh weight) in fruit flesh was 973.85 mg·hg^-1, 500.46 mg·hg^-1 in pericarp, 552.32 mg·hg^-1 in biennial stem, 389.57 mg·hg^-1 in annual branch, 736.47 mg·hg^-1 in petal, and 604.64 mg·hg^-1 in filament. The flavoring AAs and medicinal AAs were abundant. The flavoring AAs in the fruit flesh, pericarps, biennial stems, annual branches, petals, and filaments were 58.02%, 62.45%, 58.46%, 58.18%, 61.79%, and 60.66%, respectively; and, the medicinal AAs were 65.58%, 64.05%, 62.63%, 61.39%, 62.08%, and 61.73%, respectively. According to the analytical results, development and utilization of pitaya flowers and stems were suggested. The effect of saline habitat on the AA contents in parts of the plants grown on it was discussed.