The utility model discloses a portable workbench which comprises a workbench top, two telescopic brackets and a bearing plate. The workbench top is fixedly arranged on the two telescopic brackets, two slide rails are arranged on the bottom surface of the workbench top, and the bearing plate is arranged between the two slide rails, therefore the overall structure is compact, the occupation space is small, and the workbench is convenient to carry after being folded up. A limiting hole is formed on the bearing plate, a limiting screw passes through the limiting hole to be connected with the bottom surface of the workbench top, and a hole used for placing a cup or a plurality of grooves used for placing articles are formed on the bearing plate, therefore cups, stationary articles or tools can be placed on the workbench, and work, field operation or maintenance is convenient. Furthermore, a notebook computer or a maintenance tool with larger volume can be placed on the workbench. As a large amount of articles can be placed on the workbench stably, the work efficiency is improved, the articles cannot fall off easily, and the use is safe and reliable.