An obfuscated identifier detection method based on natural language processing includes: converting an input obfuscated apk to smali code level, inspecting an obfuscated string in identifiers of the smali code acquired from a smali code converter, extracting information necessary for deobfuscation and frequency of the identifiers when there is the obfuscated string, storing frequency, type and name information of identifiers calculated from information extracted from an unobfuscated apk, and acquiring and deobfuscating an identifier type name having a most similar frequency in an identifier name database (DB) using information extracted from an obfuscated information extractor. Accordingly, it is possible to reduce delay in analysis and achieve faster analysis by automatically renaming the code that is difficult to understand due to identifier conversion obfuscation.