A light source module, comprising: a substrate, a light emitting unit, provided on the substrate, and a light distribution element, comprising: a light incident surface, which is in a shape of a smooth inward concave curved surface and forms an accommodation cavity for accommodating the light emitting unit; and a light emitting surface, which is in a shape of a smooth outward convex curved surface and is opposite to the light incident surface, wherein a thickness difference is between the light incident surface and the light emitting surface, and wherein the light emitting surface comprises a center point, the center point of the light emitting surface is staggered with a center point of the light incident surface in a vertical direction and and wherein the light distribution element comprises a bottom surface surrounding a peripheral side of the light incident surface and the bottom surface is flat; and configured for being directly attached to the substrate; wherein the light distribution element is mounted to the substrate and covers the light emitting unit, and the light emitting unit is located in the accommodation cavity of the light distribution element and is aligned with the center point of the light emitting surface in a vertical direction, wherein each of the light incident surface and the light emitting surface has a cross cutting line (112, 122) and a rip cutting line (113, 123) for dividing into four quadrants, and both the light incident surface and the light emitting surface are symmetric in the four quadrants, characterized in that the light emitting unit is located on the point of intersection of the light emitting rip cutting line with the light emitting cross cutting line of the light emitting surface, such that the light emitting unit is aligned with the center point of the light emitting surface in the vertical direction. a substrate, a light emitting unit, provided on the substrate, and a light distribution element, comprising: a light incident surface, which is in a shape of a smooth inward concave curved surface and forms an accommodation cavity for accommodating the light emitting unit; and a light emitting surface, which is in a shape of a smooth outward convex curved surface and is opposite to the light incident surface, wherein a thickness difference is between the light incident surface and the light emitting surface, and wherein the light emitting surface comprises a center point, the center point of the light emitting surface is staggered with a center point of the light incident surface in a vertical direction and and wherein the light distribution element comprises a bottom surface surrounding a peripheral side of the light incident surface and the bottom surface is flat; and configured for being directly attached to the substrate; wherein the light distribution element is mounted to the substrate and covers the light emitting unit, and the light emitting unit is located in the accommodation cavity of the light distribution element and is aligned with the center point of the light emitting surface in a vertical direction, wherein each of the light incident surface and the light emitting surface has a cross cutting line (112, 122) and a rip cutting line (113, 123) for dividing into four quadrants, and both the light incident surface and the light emitting surface are symmetric in the four quadrants, characterized in that the light emitting unit is located on the point of intersection of the light emitting rip cutting line with the light emitting cross cutting line of the light emitting surface, such that the light emitting unit is aligned with the center point of the light emitting surface in the vertical direction. a light incident surface, which is in a shape of a smooth inward concave curved surface and forms an accommodation cavity for accommodating the light emitting unit; and a light emitting surface, which is in a shape of a smooth outward convex curved surface and is opposite to the light incident surface, wherein a thickness difference is between the light incident surface and the light emitting surface, and wherein the light emitting surface comprises a center point, the center point of the light emitting surface is staggered with a center point of the light incident surface in a vertical direction and and wherein the light distribution element comprises a bottom surface surrounding a peripheral side of the light incident surface and the bottom surface is flat; and configured for being directly attached to the substrate; wherein the light distribution element is mounted to the substrate and covers the light emitting unit, and the light emitting unit is located in the accommodation cavity of the light distribution element and is aligned with the center point of the light emitting surface in a vertical direction, wherein each of the light incident surface and the light emitting surface has a cross cutting line (112, 122) and a rip cutting line (113, 123) for dividing into four quadrants, and both the light incident surface and the light emitting surface are symmetric in the four quadrants, characterized in that the light emitting unit is located on the point of intersection of the light emitting rip cutting line with the light emitting cross cutting line of the light emitting surface, such that the light emitting unit is aligned with the center point of the light emitting surface in the vertical direction.