The method for high-quality and high-yield quinoa cultivation in saline-alkali soil involves creating a central elevated slope with lower surrounding edges in the field. Embankments are constructed along the lowered peripheral edges to enclose the field, and drainage ditches are excavated outside these embankments. The field is rapidly flood-irrigated until the water level reaches 20 cm above the ground surface, maintaining this water level for 10-15 hours to ensure infiltration to at least 30 cm below the surface. Simultaneously, dig out drainage outlets in the peripheral embankments to enable synchronized discharge of field water into the surrounding drainage ditches for salt-removing. This invention first reduces soil salinity and alkalinity through desalination, then precisely controls soil saline-alkali levels to meet crop requirements. The method ensures excellent soil adaptability and improvement effects throughout quinoa growth stages from germination to maturity, enabling effective saline soil utilization while enhancing crop productivity.