A direct-lit backlight source, comprising: a light-emitting unit array and a diffusion plate disposed at a light-exiting side of the light-emitting unit array, the light-emitting unit array comprising a plurality of light-emitting units arranged in an array of rows along a first direction and columns along a second direction, wherein the plurality of light-emitting units are arranged in axial symmetry with a central line of the light-emitting unit array along the first direction and a central line of the light-emitting unit array along the second direction serving as symmetry axes, respectively; the light-emitting unit array comprises a third region of columns, and further comprises a first region of columns and a second region of columns sequentially arranged in the first direction between a first edge of the direct-lit backlight source extending along the second direction and the third region, and the central line along the second direction is a symmetry axis of the third region; the light-emitting unit array comprises a sixth region of rows, and further comprises a fourth region of rows and a fifth region of rows sequentially arranged in the second direction between a second edge of the direct-lit backlight source extending along the first direction and the sixth region, and the central line along the first direction is a symmetry axis of the sixth region; light-emitting units adjacent along the first direction in the first region have a first pitch, light-emitting units adjacent along the first direction in the second region have a second pitch, light-emitting units adjacent along the first direction in the third region have a third pitch, light-emitting units adjacent along the second direction in the fourth region have a fourth pitch, light-emitting units adjacent along the second direction in the fifth region have a fifth pitch, and light-emitting units adjacent along the second direction in the sixth region have a sixth pitch; the second pitch is greater than the first pitch and is greater than the third pitch, the fifth pitch is greater than the fourth pitch, and the third pitch is greater than the first pitch; the sixth pitch is greater than the fourth pitch, and the fifth pitch is greater than the sixth pitch; a distance from the light-exiting surface of the light-emitting unit to the diffusion plate is in a range of 30 mm - 35 mm, the second pitch is in a range of 120 mm - 150 mm, and the fifth pitch is in a range of 120 mm - 150 mm. a light-emitting unit array and a diffusion plate disposed at a light-exiting side of the light-emitting unit array, the light-emitting unit array comprising a plurality of light-emitting units arranged in an array of rows along a first direction and columns along a second direction, wherein the plurality of light-emitting units are arranged in axial symmetry with a central line of the light-emitting unit array along the first direction and a central line of the light-emitting unit array along the second direction serving as symmetry axes, respectively; the light-emitting unit array comprises a third region of columns, and further comprises a first region of columns and a second region of columns sequentially arranged in the first direction between a first edge of the direct-lit backlight source extending along the second direction and the third region, and the central line along the second direction is a symmetry axis of the third region; the light-emitting unit array comprises a sixth region of rows, and further comprises a fourth region of rows and a fifth region of rows sequentially arranged in the second direction between a second edge of the direct-lit backlight source extending along the first direction and the sixth region, and the central line along the first direction is a symmetry axis of the sixth region; light-emitting units adjacent along the first direction in the first region have a first pitch, light-emitting units adjacent along the first direction in the second region have a second pitch, light-emitting units adjacent along the first direction in the third region have a third pitch, light-emitting units adjacent along the second direction in the fourth region have a fourth pitch, light-emitting units adjacent along the second direction in the fifth region have a fifth pitch, and light-emitting units adjacent along the second direction in the sixth region have a sixth pitch; the second pitch is greater than the first pitch and is greater than the third pitch, the fifth pitch is greater than the fourth pitch, and the third pitch is greater than the first pitch; the sixth pitch is greater than the fourth pitch, and the fifth pitch is greater than the sixth pitch; a distance from the light-exiting surface of the light-emitting unit to the diffusion plate is in a range of 30 mm - 35 mm, the second pitch is in a range of 120 mm - 150 mm, and the fifth pitch is in a range of 120 mm - 150 mm.