In order to achieve the phase-sensitive probe gain without population inversion, we investigate a four-level atomic system, where the probe field is controlled by a three-level closed loop subsystem. In the case of three-photon resonance, large steady-state inversionless probe gain can be obtained. Owing to the quantum interference, the probe gain is sensitive to the relative phase of the three-level closed loop subsystem. The intensities of the fields of the three-level closed loop subsystem are also important factors that can result in different gain behaviors of the probe field.