This paper investigated how the sentence structure has transformed in Korean annotations of Nogeoldae Chinese Language Textbooks. The cause of these changes does originate neither from different periods nor the different translators. But it comes from contextual meaning and expression modes which are getting similar to the contemporary Korean with the transition of the late middle Korean to the modern Korean. The following is the summary of the detailed changes. 1) Changes in transition of simple sentence of the 16th century` to compound complex sentence in the 17th and 18th century: When the simple sentence structure changed into the complex sentence, the declarative ``-다`` is most frequently used in the closing ending; the restrictive mood ``-으니`` is most frequently used in the conjunctive ending. Although ``-으니`` among its various meanings was generally used for the continuing explanation in the sentence, it has different mood in the use of ``-으니`` in the contemporary Korean which used to mean the cause and the condition. When the simple sentence of conversation changes into the compound one which require a little more explanation, it would be effective to use ``-으니`` for its meaning of the continuing explanation. 2) Ganges in transition of the 16th century`s compound complex sentence to the 17th and 18th century`s simple sentence: The restrictive mood ``-으니`` is most frequently used in the conjunctive ending and the declarative ``-다`` in the closing ending. Since 16th-Nogeoldae is the reference material which mainly consists of simple conversation sentences, the transformation from the compound structure to the simple one cannot be much seen like the above 1. When the compound structure sentence with conjunctive endings does not make sense or look awkward from the perspective of the contemporary Korean, it changed into the simple sentence. With the transition from the late middle Korean to the modern Korean, expression and meaning are getting closer to the contemporary Korean through the transformation of sentence structure.