The present invention provides a semiconductor test structure for MOSFET noise testing. The semiconductor test structure includes: a MOSFET device having a first conductivity type formed on a first well region of a semiconductor substrate; a metal shielding layer formed on the MOSFET device, the metal shielding layer completely covering the MOSFET device and extending beyond the circumference of the first well region; a deep well region having a second conductivity type formed in the semiconductor substrate close to the bottom surface of the first well region, the deep well region extending beyond the circumference of the first well region; wherein a vertical via is formed between the portion of the metal shielding layer extending beyond the first well region and the portion of the deep well region extending beyond the first well region to couple the metal shielding layer to the deep well region. The metal shielding layer is used to be connected to the ground terminal of a testing machine during testing, and the first conductivity type and the second conductivity type are opposite conductivity types.