The invention discloses a round silicon thin film solar cell and a fabrication method thereof. The cell is composed of cell units connected in series, and takes a transparent substrate as a substrate, comprises a front electrode layer, a silicon thin film layer, a back electrode layer and a back paint layer which are stacked up in sequence. The round silicon thin film solar cell is characterized in that working faces of the cell units are formed by laser scribing, an external envelope takes an arc shape, a working face inside the cell is composed of n serially connected cell units which have equal effective area, n is not less than 2, at least two shielding lines and a laser scribing line or a dot-and-dash line which connects a positive electrode and a negative electrode are arranged between the positive electrode and the negative electrode of the cell, and the width between the positive electrode and the negative electrode is 0.03-0.10mm. The fabrication method adopts advanced laser marking technology, can scribe the cell units with fan-shaped or irregular figures, has high precision, and causes the width of an invalid region inside the solar cell to decrease from 0.5-1.8mm to 0.03-0.20mm, thus enlarging the effective working area of the cell.