An optoelectronic semiconductor structure includes a first n-type semiconductor layer, a first quantum well layer, a first p-type semiconductor layer, and a second n-type semiconductor layer. The first quantum well layer is disposed on the first n-type semiconductor layer. The first p-type semiconductor layer is disposed on the first quantum well layer. The second n-type semiconductor layer is disposed on the first p-type semiconductor layer. The second n-type semiconductor layer includes both an n-type dopant and a p-type dopant. The concentration of the n-type dopant in the second n-type semiconductor layer is greater than the concentration of the p-type dopant in the second n-type semiconductor layer. The first n-type semiconductor layer, the first quantum well layer, the first p-type semiconductor layer, and the second n-type semiconductor layer form a bipolar phototransistor structure. A manufacturing method of the optoelectronic semiconductor structure is also provided.