A high transmittance thin film solar panel includes a transparent substrate, a front electrode layer, a light absorption layer and a rear electrode layer. The light absorption layer is formed with opening patterns with the same width at positions aligned correspondingly to form at least one first opening trench, a plurality of second opening trenches with continuously and periodically sinusoidal-wave shape, and a plurality of third opening trenches parallel to, interlace with or superpose the second opening trenches, and extend in a direction orthogonal to the direction of the first opening trench. The high transmittance thin film solar panel of the present invention is mainly used for green buildings. The opening trenches of the high transmittance thin film solar panel are formed in a manner of curve shape by an oscillating laser head, and can enhance the transmittance by more than about 3% in comparison with the conventional one.