Multimodal biometric system utilizes two or more character modalities, e.g., face, ear, and fingerprint, Signature, plamprint to improve the recognition accuracy of conventional unimodal methods. We propose a new dimensionality reduction method called Dimension Diminish Projection (DDP) in this paper. DDP can not only preserve local information by capturing the intra-modal geometry, but also extract between-class relevant structures for classification effectively. Experimental results show that our proposed method performs better than other algorithms including PCA, LDA and MFA.