To overcome the difficulty of all-range and all-azimuth automatic track initiation in the dense clutter environment, the concept of grid connection is adopted for grid partitioning of the observation space to form an independent connected area based on certain criteria, according to the spatial distribution characteristics of clutters and targets. The trace points are preprocessed based on the analysis of the connected area. After the pre-processing, the track-initiation processing is implemented by using the measurements of targets. The calculation cost is reduced by means of decreasing the number of observation points used for judging track initiation, and thus the automatic track initiation is implemented rapidly. The feasibility of the method in engineering applications has been verified by simulations and the actual data.