The invention discloses a forecasting method for improving natural offspring seed collection efficiency of Crassostrea hongkongensis. According to the forecasting method disclosed by the invention, through links: larva sample collection, phenotype classification, molecular recognition, comprehensive evaluation, timely offspring seed collection and the like, a large number of Crassostrea hongkongensis juvenile mollusks can be successfully obtained from a natural sea area. Not only is the natural seed collection amount improved and the offspring seed quality ensured but also the problems of unstable amount, mixed types and multiple repeated collection caused by blind offspring seed collection in the past are solved, and therefore, sufficient offspring seed sources are provided for the resource recovery of the Crassostrea hongkongensis and the development of the culture industry of the Crassostrea hongkongensis.