Research conclusions: The va lue of 2C mutua l deviat ion w as simulated by add ing the random error confo rmed to the norma l distribu tion, and the simu lation calcu lation o f the partia l date of one passenger dedicated line w as made,acco rd ing to the fie ld observationm ethod and features as w e ll as measurement situat ion of ballastless track CPIII p lane netw ork . The ana lysi resu lt show ed the 2C mutua l deviat ion has certain impact on the accuracy o fCPIII plane netw ork. But under the prem ise o f hav ing good in itial calcu lation data and little pro ject ion distort ion, the main measurement prec isions o f CPIII p lane netwo rk could meet the specificat ion requ irement by w iden ing the 2C mutual dev iation to 15 seconds. Such w idening the 2C mutual dev iation cou ld enhance the measurement efficiency o f CPIII p lane netw ork and prov ide he fundam enta l data for the rev ision and improvement o f the eng ineering survey specif ication for h igh- speed ra ilw ay.