Based on the remote,ensing information feature of Nansha coral inlet, and reef, that controlled by the Nansha Islands local area's geological structure and growth law, by means of mathematical model and PC, the Nansha Islands coral islets and reefs' top geological data' spatial distribution and local change trend are simulated by using the trend surface system on the remote sensing composite information, and an scientific interpretation and local comparison of Nansha coral islands and islets' spatial distribution feature are made.