Using Monte Carlo simulation techniques, we focus on the physical gelation behavior and conformation change under the existence of additional monovalent salt, which provides screening to the electrostatic interaction of charged telechelic polyelectrolyte chains and causes new balance between hydrophobic interaction. of end groups and electrostatic interaction originated from the polyelectrolyte blocks. For the electrostatic interaction dominated system, the screening effects will decrease the electrostatic repulsion between small sized clusters and enable the further aggregation of TP chains, resulting in prompting the sol-gel transition progress; for the short-range attraction dominated system, the screening effects present a complicated phenomenon, which includes the prompting effect at the beginning of sol-gel and a hindering effect when the gelation progress is close to an end.