A multi-primary color conversion method is provided to include: establishing a spatial gamut model of a display panel; determining a target peripheral surface corresponding to the target color according to the color coordinates of the target color and color coordinates of a color corresponding to each vertex of each peripheral surface; obtaining reference gray scales of a part of primary colors of the target color according to gray scales of the primary colors of a color corresponding to each vertex of the target peripheral surface; obtaining reference gray scales of the rest primary colors of the target color and a reference luminance of the target color; and respectively converting the reference gray scales of the plurality of primary colors of the target color into target gray scales according to a proportional relationship between the reference luminance and the target luminance of the target color.