A system performance prediction method and apparatus where the transmission system performance prediction apparatus includes: a calculating unit configured to calculate system performance at second power according to first power of a signal and a first noise component generated by the system at the first power. With the above system performance prediction apparatus, by changing power and predicting the system performance by using noise components at different power, accuracy of the prediction of the system performance may be improved, and problems in the related art may be avoided that in predicting system performance, a large-capacity database needs to be prepared and accuracy of the prediction of the system performance is low.