We report an experimental observation of the optical transparency enhancement resonances in Hanleelectromagnetically induced transparency (EIT) configuration with a microwave field excitation. In this experimental system, a strong control field and a weak probe field form three-level Λ-type configurations of EIT. The fourth level is coupled by an additional microwave field. With the microwave field excitation, the probe field undergoes a process of absorption to transparency when the probe field decreases. Compared with the EIT effect, this result indicates optical transparency enhancement. A simple theoretical model and a numerical simulation are presented to explain the observed experimental results. The applications of these optical features are also discussed. We report an experimental observation of the optical transparency enhancement resonances in Hanle electromagnetically induced transparency (EIT) configuration with a microwave field excitation. In this experimental system, a strong control field and a weak probe field form three-level Λ-type configurations of EIT. With the microwave field excitation, the probe field undergoes a process of absorption to transparency when the probe field undergoes a process of absorption to transparency when the probe field undergoes a process of absorption to transparency when the probe field undergoes a process of absorption to transparency and a numerical simulation are presented to explain the observed experimental results. The applications of these optical features are also discussed.