In this paper, we study a novel pattern in the fingerprint called crease, a kind of stripes irregularly crossing the normal fingerprint patterns (ridges and valleys). Creases will cause spurious minutiae by using conventional feature detection algorithm, and therefore decrease the recognition rate of fingerprint identification. By representing the crease using a parameterized rectangle, we design an optimal filter as a detector. We employ a multi-channel filtering frame-work to detect creases in different orientations. In each channel, PCA is used to extract rectangles? parameters from the raw detected results. Our algorithm is demonstrated by experiments.