The parameter errors of the flat-field holographic concave grating including radius error, recording geometry error and use geometry error are induced by the fabrication and usage. In order to give theoretical guidance to the design and assembly of the spectrometers, the geometric ray-tracing method is used to analyze the image widths and the meridian focal lines for different parameter errors. It is discovered that, for a great parameter error range, there are parallel displacement and tilt which affect the parameter errors. The numerical calculation results indicate that, in a large neighborhood around the design point, the parameter errors can be compensated by each other and the spectral resolution can be as good as designed after compensation of the errors.