A parallel correlation method and a correlation apparatus are provided, which can be adapted for an optical navigation device. The method includes: generating a reference array corresponding to a reference image and a compare array corresponding to a first compare image captured are generated; storing the reference array in a first memory bank such that the reference pixel values of an ith column thereof are indexed by the respective ith column; storing the compare array in a second memory bank such that the compare pixel values of a jth column thereof are indexed by the respective jth column; fetching the compare pixel values from the second memory bank and the corresponding reference pixel values with column indexing to simultaneously compute the correlation between the reference array and the compare array for a L×M correlation array, wherein M, i, and j are integers.