An apparatus for a learn control of an automatic transmission includes a storage unit configured to store an initial fill time value and a gain value corresponding to a revolution per minute (RPM) peak to peak of a turbine. An oil pressure applier is configured to apply an oil pressure to a non-operating friction element. An RPM measurer is configured to measure the RPM of the turbine, and a learn controller is configured to control the oil pressure applier to apply the oil pressure to the non-operating friction element during a preset reference time and control the initial fill time based on the RPM peak to peak of the turbine showing a difference between a measured value RPM of the turbine measured by the RPM measurer and a preset targeted value while a vehicle is in a coasting operation in an in gear state.