ISDS arbitrator has obvious identity, geographical origin and gender characteristics. In order to solve the problem of unbalanced distribution of investment arbitrator, ICSID has begun to choose female arbitrators or arbitrators from developing countries. The natural arguments of the parties as well as the repeated interactions among the arbitrators, results in the risk of perception, the risk of compromise and the risk of bias. Extending the jurisdiction of arbitration and maintaining the interests of the ISDS system are the two main incentive paths for the arbitrator. Different parties in the ISDS have a problem of unequal information or information asymmetry when choosing arbitrators, which will result in the production of the gray market of the arbitrators and influence on ISDS arbitration procedure. The arbitrators disclose the relationship with the parties and the potential conflict in a timely and thorough manner is very important to guarantee the independence and impartiality of the arbitrators. The dual identity of the arbitrator is prone to make disputes conflict, which will lead to the problem of due process. The disclosure of the reasonable suspicion situation and the formulation of the conduct code for the arbitrator can eliminate the conflict to a certain extent.