Chopped maize have to be compressed in bunker silos for high quality silage. High losses can occur if the compaction is too low. The main objective of this research was to determine the compaction force at the ensiled material in bunker silo. A pressure measurement method was developed. This method is based on the compaction force determination. Mesens 500 series 4-20 mA of the 4 bar capacity pressure sensor was used. Sensor capacity was determined by the tractor tire pressure. In bunker silos were identified measure points to characterize the silage compaction profile. The experiment was organized in a 3 layer thickness (0.5 m, 1 m, 1.5 m) x three lateral positions (left near the wall, right near the wall and centre) x three areas (A, B and C). Sensors were located during filled the each layer in the bunker silos. Results indicate that a higher compaction force was measured by decreasing layer thickness and by increasing compaction time. The highest pressure was measured in C area due to the higher compaction time.