PN-sequence padding scheme has been proposed in TDS-OFDM systems instead of the cyclic prefix scheme in the traditional CP-OFDM systems. The PN-sequence, padded between normal OFDM symbols, has dual functions for assisting in channel estimation and preventing inter-symbol-interference between normal OFDM symbols over frequency-selective fading channel. However there are lSI to the normal OFDM symbols caused by the padding PN-sequence, referred to as PN-ISI. Therefore it is crucial to remove the PN-ISI in TDS-OFDM systems. In this paper, we propose a scheme which performs the channel estimation/equalization and the subtraction of PN-ISI jointly. Comparing to the normal scheme which performs the PN-ISI removal after channel estimation without iteration, the performance of the proposed scheme is shown to be superior with simulations.