A novel acoustic modeling method for Chinese speech recognition based on Intra-Syllable Dependent Phone (ISDP) set is proposed. The ISDP set extends the traditional phone set based on the intra-syllable information of Chinese phonetic knowledge. The acoustic models based on ISDP set (ISDPMs) have the following features. First, they are suitable for the case of a rather small scale of training data. Second, this scheme is an integration form of the tri-phone modeling and the syllable modeling. The mixed Gaussian densities are used to describe the feature space of each ISDP and the Viterbi algorithm is adopted for decoding process. In addition, the ISDP-syllable search tree is designed and presented to reduce the decoding complexity. Our Experimental result shows that the ISDP modeling is more flexible and faster than the syllable modeling meanwhile it causes no much performance reduction. Keywords: Chinese speech recognition, intra-syllable dependent phone based models (ISDPMs), mixed Gaussian density, ISDPsyllable search tree