In this study, the effects of flow force applied to the spool in electrohydraulic servovalve on the valve's performances are investigated. First, experiments investigating flow force in an electrohydraulic servovalve is conducted, and various physical parameters of the servovalve are measured. Then, a simulation program for the valve was developed based on the full mathematical model of the servovalve, using the measured physical parameters' values and the experimental results on the flow force. The effects of the flow force on the valve performances are described in detail based on the simulation results.