Why ac unit is blowing hot air inside the house but outside unit blows cold air?

Sounds like your system is a heat pump. When a heat pump cools in the summer, the inside coil gets cold and the outside coil gets hot. When the heat pump heats in the winter, the inside coil gets hot, and the outside coil gets cold. It sounds like your heat pump is stuck in heating mode. Check your thermostat to be sure it didn't accidentally get switched to heat. It could be the reversing valve inside the unit is stuck, or an electrical control is broken, forcing the reversing valve to stay in the heating position. Perhaps a call to the serviceman is in order!