A single cylindrical reflector usually has defects of distortional imaging beam and limited field of view usually less than 1°. A three cylindrical reflectors system is presented to overcome these defects. Based on the ray tracing of cylindrical reflector, a three circularly cylindrical reflectors and a three conic-cylindrical reflectors system have been designed. The full field of view (FOV) has reached 3° in tangential plane; on the edge of FOV, the modulation transfer function (MTF) of the former design at 45 lp/mm is better than 0.2 and the latter is better than 0.6. A new optimization method using parabolic-cylindrical reflector is presented. This method can be used to optimize the MTF in tangential plane, and the final MTF satisfies the requirement of the high spatial resolution in imaging spectrometer field.