High-energy heavy-ion collisions produce abundant hyperons and nucleons. A dynamical coales- cence model coupled with the ART model is employed to study the production probabilities of light clusters, deuteron （d）, triton （t）, helion （3He）, and hypertriton （~H） at subthreshold energy of A production （= 1 GeV per nucleon）. We study the dependence on the reaction system size of the coalescence penalty factor per additional nucleon and entropy per nucleon. The Strangeness Population Factor （S3 =3H/（3He ×∧/p）） shows an extra suppression of hypertriton comparing to light clusters of the same mass number. This model predicts a hypertriton production cross-section of a few μb in ^36Ar＋^36Ar, ^40Ca＋^40Ca and ^56Ni＋^56Ni in 1 A GeV reactions. The production rate is as high as a few hypertritons per million collisions, which shows that the fixed-target heavy-ion collisions at CSR （Lanzhou/China） at A subthreshold energy are suitable for breaking new ground in hypernuclear physics.
