Hy-1 is a first China’s ocean color satellite which will be launched as a piggyback satellite on FY-1 satellite using Long March rocket.On the satellite there are two sensors:one is the China’s ocean color and temperature scanner(COCTS),the other is CCD coastal zone imager(CZI).The COCTS is considered to be a main sensor to play a key role.In order to understand the characteristics of future ocean color images observed,a simulation and ealuation study on the quality and availability of the COCTS image has been done.First,the simulation models are introduced briefly,and typical simulated cases of radiance images at visible bands are introduced,in which the radiance distribution is based on geographic location,the satellite orbital parameters and sensor properties,the simulated method to evaluate the image quality and availability is developed by using the characteristics of image called the complex signal noise ratio(CSNR).Meanwhile,a series of the CSNR images are generated from the simulated radiance components for different cases,which can be used to evaluate the quality and availability of the COCTS images before the HY-1 is placed in orbit.Finally,the quality and availability of the COCTS images are quantitatively analyzed with the simulated CSNR data. The results will be beneficial to all scientists who are in charge of the COCTS mission and to those who plan to use the data from the COCTS. Hy-1 is a first China’s ocean color satellite which will be launched as a piggyback satellite on FY-1 satellite using Long March rocket. Where the satellite there are two sensors: one is the China’s ocean color and temperature scanner (COCTS), the other is CCD coastal zone imager (CZI). The COCTS is considered to be a main sensor to play a key role. In order to understand the characteristics of future ocean color images observed, a simulation and ealuation study on the quality and availability of the COCTS image has been done. First, the simulation models are introduced briefly, and typical simulated cases of radiance images at visible bands are introduced, where the radiance distribution is based on geographic location, the satellite orbital parameters and sensor properties, the simulated method to evaluate the image quality and availability is developed by using the characteristics of image called the complex signal noise ratio (CSNR). While, a series of the CSNR images are generated from the sim ulated radiance components for different cases, which can be used to evaluate the quality and availability of the COCTS images before the HY-1 is placed in orbit. Finaally, the quality and availability of the the COCTS images are quantitatively analyzed with the simulated CSNR data. The results will be beneficial to all scientists who are in charge of the COCTS mission and to those who plan to use the data from the COCTS.