Using germplasms Dracocephalum moldavica No.1, Baihua Dracocephalum moldavica L., Shandong Dracocephalum moldavica L., Gansu Dracocephalum moldavica L. and Xinjiang Dracocephalum moldavica L. seeds as materials, we explored the effects of the harvest period (flowering stage, final flowering stage, mature stage) on the growth physiological characteristics, yield of medicinal herbs and the content of pharmacodynamic components of different germplasm of D. moldavica L. in salinealkali land, to provide a reference for the popularization and planting of D. moldavica L. in salinealkali land of central Inner Mongolia. The results showed that: (1) with the delay of the harvest period, the fresh weight of all germplasms of D. moldavica L. decreased gradually, and the flowering stage was the best; while the plant height and other morphological growth indexes increased gradually, and the mature stage was the best. (2) Antioxidant enzyme activity, Osmotic regulatory substances and other physiological indexes of stress resistance decreased gradually, and the flowering stage was the best. (3) The photosynthetic gas exchange parameters decreased gradually, and the flowering stage was the best. (4) The yield increased first and then decreased, and the final flowering stage was the best; while the content of pharmacodynamic components decreased gradually, and the flowering stage was the best. Among them, the yield of Dracocephalum moldavica No.1 at the final flowering stage was the highest (4 692.32 kg·hm^-2); the content of pharmacodynamic components of Xinjiang D. moldavica L. was the highest in the flowering stage, the content of total flavonoid reached 23.40 mg·g^-1, essential oil content up to 0.59%. The research shows that, in various combinations of germplasm and harvesting period, the yield of Dracocephalum moldavica No.1 in the final flowering stage was the highest, and the flowering period of Xinjiang Dracocephalum moldavica L. had the highest growth characteristics and pharmacodynamic content. In cultivation practice, Dracocephalum moldavica No.1 can be selected for yield and harvested at the final flowering stage, and Xinjiang Dracocephalum moldavica L. can be selected for the pursuit of medical and harvested at the flowering stage.