The optical characteristics of linearly chirped fiber Bragg gratings with different types of apodising func2 tions that we contruct are calculated numerically using matrix method ,and we compare them with the best property of gaussian linearly chirped grating. Some valuable conclusions are obtained. We think a linearly chirped fiber Bragg grating with this apodized function is more practicable than the one with gaussian function. This paper can provide certain theoretical evidence for the design and facture of the fiber Bragg grating as dispersion compensator.