Abstract: Airborne maritime surveillance radar adopts fast scanning beam and scan to scan integration technology to ensure the detection of slow moving targets in strong sea clutter background. The technology can suppress long correlation sea spike effectively, but suffer detection ability decline in noise background, comparing to conventional slow scanning detection strategy. Aiming at the technology, an analysis of the detection gain under condition of different scanning speed in sea clutter zone is made firstly in this paper, then the detection loss in noise zone is evaluated, caused by three acting factors. Taking clutter zone detection gain and noise zone detection loss in account, the advises of airborne maritime surveillance radar operation modes selection and combination are presented. Main research achievements in the paper have important meaning and value for the design of maritime surveillance radar.