If it's the dash airbag light (the one near the radio and AC controls), it's controlled by a weight sensor in the passenger seat. It'll turn on if someone's sitting there or if you set something heavy in the seat. It's just to notify you that it's working.
If it's the HUD airbag light (near the speedometer), then there's a problem with the driver side airbag.
If it's the HUD airbag light (near the speedometer), then there's a problem with the driver side airbag.