The invention relates to an array type wave monitoring device and a wave measurement method. The device comprises a horizontal bracket of a fixed device, the horizontal bracket is provided with at least three water level meters in triangular distribution, and the three water level meters are at a same horizontal height; and the three water level meters are connected with a computer processing terminal by transmission lines and a signal conversion device. The method is to calculate the times tau AB and tau AC of wave from the first water level meter to the second water level meter and the third water level meter by utilizing any water level meter to measure wave height and cycle and utilizing the three angled water level metes according to a cross-correlation time-delay principle, and according to tau AB and tau AC and distances and angles among the water level metes, wave direction, wave speed and wave length lambda is equal to c multiplied by T0 are calculated.