The present invention discloses a network connection establishing method capable of preventing a link procedure from being strangled in a training state. An embodiment of the method comprises: a preceding step; a training step; and a following step. Said training step includes at least one of the following: counting a number, and returning to the preceding step if a local receiver is not yet ready after finishing counting the number; detecting a reception signal according to a signal detection level, and returning to the preceding step when none of the reception signal is detected; determining a number of level(s) of the reception signal, and returning to the preceding step if the number of level(s) is less than an expected level number; and comparing a signal-to-noise ratio of the reception signal with a signal-to-noise threshold, and returning to the preceding step when the signal-to-noise ratio fails to satisfy the signal-to-noise threshold.