A digital modeling method for dialect protection and cultural inheritance was proposed to solve the problems of dispersive resources of Chinese dialects, difficulties in phonetic transcription and insufficient cultural semantic correlation. The CDCC-2025 Chinese dialect culture corpus is constructed, which contains six types of dialect areas, 120 hours of speech, 36000 speech samples, 18000 dialect texts, 6200 cultural entities and 14800 relation triples. Method The acoustic coding model is used to complete dialect speech recognition, and the two-tower semantic alignment algorithm is used to establish the mapping between dialect words and Mandarin paraphrases. The regional cultural knowledge graph and attention fusion mechanism are combined to realize multimodal resource retrieval. Experimental results show that the dialect recognition accuracy of the proposed method reaches 94.2%, the F1-score is 93.5%, and the WER is reduced to 8.9%. Semantic retrieval Recall@10 reaches 91.6% and MRR reaches 0.846. Triple F1 of knowledge graph achieves 89.3%. The results show that the proposed method can improve the effect of dialect speech recognition, cultural semantic organization and digital retrieval.