A uniform surface light source which is formed by assembly belongs to the technical field of packaging and application of light-emitting diodes. The uniform surface light source is characterized in that the uniform surface light source is formed by horizontally assembling a plurality of light-emitting diode-based surface light source modules, and each surface light source module comprises a light-emitting diode light source and a uniform light-collimation optical mechanism which leads light emitted by the light-emitting diode light source to generate similar uniform illumination on an emergent plane after the refraction and/or reflection and leads the emergent direction to be parallel to the central axis of the light. The collimation mechanism is a collimation panel, the center thereof is a convex lens, the periphery is a group of prisms with cross sections which are congruent triangles, and the projections of the prisms on an orthogonal plane of the central axis are a group of concentric circles. The uniform surface light source can obtain good uniformity of emergent light under the premise of ensuring high efficiency, thereby having broad prospects in backlight sources of liquid crystal display devices which are arranged in personal computers, vehicle navigation systems, handheld telephones and other devices, lamps for ordinary indoor lighting and other application aspects.