The article uses the nasometer to analyze systematically the monophthongs, diphthongs, nasalized vowels, non-nasal voiced consonants, and nasal consonants of Shuangfeng dialect. Through the investigation of nasality, we find that it is a dialect with high value of nasality, and its nasality is gradually weakening. The nasality of vowels is related to the position of the tongue. The degree of nasality to the voiced consonant is related to the pronunciation position and the pronunciation method. Phonetically, the type of /l/ of Shuangfeng dialect has important significance and has age differences. From the perspective of the nasality, the types of /l/ of the elderly, middle-aged, and young speakers are respectively nasal /l/, nasalized /l/, and accented /l/. The nasality decreases with reduction of speakers' age.