In order to reduce the influence of dispersion induced by different fib er transmission lengths and then improve the signal quality of radio over fiber (ROF) system,we propose an ROF tr ansmission system based on tunable dispersion compensation,combining the static nonlinear chirped fiber grating and dynamic wavelength scanning.After the theoretical analysis of the proposed system,we actually fabri cate a nonlinear chirped fiber grating and make a semi physical simulation o f tunable dispersion compensation in ROF transmission with optical communication simulation softwave.Then we compare and analyze the system transmission performance with and without chirped fiber grating dispersion compensation.The simulation results show that under the same condit ions,the system effective transmission distance increases from 61km without grating to 122.5km with grat ing.When the subcarrier frequency is 20GHz and transmission distance is 61km,th e ROF system can be error free transmission with the laser frequency in the range from 1551. 3nm to 1551.45nm.The simulation results prove the tunability of dispersion compensation of the propo sed scheme in different transmission distances,different laser frequencies and different radio frequencies.