The present disclosure generally relates to a protective case for a tablet computer, includes: a front plate (110) having a first surface (111) configured to protect a display surface of the tablet computer, wherein a magnetic element (112) is installed on the first surface (111); a holding plate (120) being configured to hold a back of the tablet computer; a supporting plate (130) connecting the front plate (110) and the holding plate (120) to prop up the tablet computer; wherein the magnetic element (112) can be installed at different positions on the first surface (111), in order to enable the tablet computer to stand up at different angles. The magnetic element (112) installed on the first surface (111) of the front plate (110) is attracted with a bottom end of the tablet computer, thus a steady triangle frame is formed between the tablet computer and the folded protective case, further enabling the tablet computer to stand up at different angles.