The present study aims to examine vocabulary analysis programs suitable for English textbook authorization in the amended version of the national curriculum. The analysis of WordLister 2002, a conventional vocabulary analysis software, reveals that it fails to meet the needs necessary to authorize textbooks in terms of user-friendliness and limited uses of the vocabulary analysis output. The design of WordLister 2002 is too complicated to be used without special training. While it provides useful information on new vocabulary, it fails to provide information in comparison with the existing research on vocabulary. NLPtools, on the other hand, applies corpus analysis techniques to the analysis of textbook vocabulary. In this program, texts in the textbook are seen as a corpus. Another characteristic is that NLPtools employs analysis methods based on dictionaries. It is found that NLPtools processes special characters in the text, so that the user does not need to process them by using specified input codes as in WordLister 2002. Wordlister 2002 requires its user to register a number of words in the process of vocabulary analysis, whereas the user with NLPtools does not need to register words as its built-in dictionary has a wide range of information on words. NLPtools also provides its users with functions, by which they can get and analyze the information they need. With these advantages over the conventional software, it is suggested that NLPtools can be used as a vocabulary analysis program for textbook authorization in the amended curriculum.