In this work, I developed an algorithm to decompose a polygon area into n polygonal pieces based on each UAV’s search capability and position to explore large-scale unknown environments. In each sub-polygon area, I also devised a sweep direction adjustable Lawn Mower Search Pattern and Spiral Search Pattern methods for a UAV to search this area. Moreover, I designed an optimization planner based on the Greedy Search Strategy which guided UAVs with kinematic constraints to explore large-scale unknown environments that maximize global certainties.