The purpose of this article is to reveal a use of ``쌓다``, an auxiliary verb, is divided into a use for repeated emphasis and a use for simple emphasis, and discuss its syntactic features. ``쌓다``, an auxiliary verb, used in a form of ``-어 쌓다`` has been treated as similar to ``어 대다`` and no one has a great interest in the syntactic and semantic differences between these two auxiliary verbs. However ``어 대다`` and no one has a great interest in the syntactic and semantic differences between these two auxiliary verbs. However ``어 대다`` can be easily replaced by ``-어 쌓다`` whereas ``-어 쌓다`` is not used by being replaced by ``어 대다``, which indicates ``쌓다``, an auxiliary verb, is more widely used than ``어 대다`` in the context of meaning and function. There are severe restrictions in combining ``어 대다`` with main verbs yet there are less restrictions in combining ``-어 쌓다`` with main verbs. As ``어 대다`` can take the verbs with the property of [+repeatability] and [+mobility] as main verbs, it functions only to emphasize the repeated actions. However there are less restrictions in combining ``-어 쌓다`` with main verbs, it can be used to simply emphasize the non-repeated actions and state as well as the repeated actions. Furthermore when ``-어 쌓다`` functions as ``repeated emphasis``, it still has the meaning of a general verb ``쌓다``. If it demonstrates the negative awareness when functioning in this way, it can be replaced by ``대다``. However when it functions as ``simple emphasis``, its meaning becomes abstract and thus it cannot be either combined with non-repeated verbs nor be replaced by ``대다``. Regarding the syntactic features of ``-어 쌓다``, unlike the previous studies, it can be combined with tense prefinal endings-``었-`` and, ``-겠-`` and there are no restrictions in combining it with the adverbs with small degreed when it has the property of repeatability. Furthermore, regarding anaphora, other emphasis auxiliary verbs do not go well with the anaphora of main verbs only yet ``쌓다`` goes well with that.