A direct-lit backlight source, a manufacturing method thereof, and a display device. The direct-lit backlight source includes: a light-emitting unit array; in a first direction, the light-emitting unit array includes a third region, and a first region and a second region sequentially between a first edge and the third region; in a second direction, the light-emitting unit array includes a sixth region, and a fourth region and a fifth region sequentially between a second edge to the sixth region; light-emitting units adjacent along the first direction in the first, second, third region, have a first, second, third pitch, respectively; light-emitting units adjacent along the second direction in the fourth, fifth, sixth region, have a fourth, fifth, sixth pitch, respectively; the second pitch is greater than the first pitch and the third pitch, respectively; and the fifth pitch is greater than the fourth pitch and the sixth pitch, respectively.