The invention provides a pixel structure and an OLED display panel containing the pixel structure. Each pixel unit comprises a first sub pixel, a second sub pixel and a third sub pixel, wherein the first sub pixel and the second sub pixel are arranged in one column (row), the third sub pixel is arranged in the other column (row), and the total size of the first sub pixel and the second sub pixel along the column (row) direction is larger than the size of the third sub pixel along the column (row) direction. The arrangement structures of the pixel units in the same row (column) are the same. The arrangement structure of each pixel unit after 180-degree turning along the row (column) direction is the same with the arrangement structure of the adjacent pixel unit in the same column (row). Byusing the pixel arrangement mode, the pixel spacing is reduced, the PPI is improved, and the difficulty of the evaporation mask making process and the evaporation process can be lowered.