For the next generation of Chinese geostationary meteorological satellites (FY-4), an optical lightning mapping sensor is planned to observe lightning and storms on a real-time, continual basis. In order to fully benefit from FY-4 lightning observations，it is desirable to establish optical-band radiative transfer simulation algorithm of lightning, and investigate the properties of lightning radiative transfer and the cloud top radiation signals observed by satellite. Combined observational parameters of FY-4 lightning imager，based on the simplified lightning source and thunderstorm models, a Monte Carlo approach is applied for simulating the transfer of lightning produced photons in thunderclouds, and the outputs are designed to address the lightning radiation signatures obtained by FY-4 lightning mapping sensor. The simulated results show that lightning radiative transfer simulation based on Monte Carlo method can theoretically reveal links between satellite optical-band lightning radiation observation and the most important parameters, and provide extremely valuable information for the future application of lightning data observed by satellite.