In this paper the uncertainty component of a multisensor microwave reflectometer dependent on mutual reflections between sensors is described. One-line and two-lines arrangement of the set of sensor localization are considered. Adjacent sensors influence each other. The mathematical model of signal flow graphs of such a system was developed. The set of linear algebraic equations incorporating main reflections between sensors was worked out. The least squares method or Kalman filter for averaging the sensor signals with random distortions is used. The uncertainty of measuring the power by the multi-sensor reflectometer is estimated. The obtained results are discussed. The described methods of the uncertainty evaluation can be applied to automation of the multi-sensor reflectometer and in other multivariable measurements.