Starfire's alien physiology constantly absorbs ultraviolet radiation and converts it to energy.
She can also absorb the ultraviolet radiation from other life forms. She once used this application of her power to weaken a group of Kryptonians who otherwise require ultraviolet radiation to maintain their superhuman abilities.
Which leaves a distinctive energy contrail behind, looking as if it is coming directly from her hair. Starfire has also been stated to have flown light years through space in short amounts of time.
The solar absorption experiments performed on her by the alien Psions granted her the amazing power and ability to channel and project that same energy into destructive blasts called "starbolts". Starfire also has the power and ability to unleash all her stored energy into a pseudo nova blast. It is suggested to be as hot as the sun itself and so only uses this in dire situations.
When angered, Starfire can go into a berserker state, granting her even greater strength, invulnerability, and immunity to many forms of damage. She is highly resistant to injury and can even survive unharmed in the cold vacuum of space.
Starfire possesses great superhuman strength despite her pin-up girl looks. She can out-muscle her Titans teammates Cyborg and even Donna Troy as even Donna Troy could not restrain her and needed Mon-El's help in doing so.
She is also capable of assimilating other languages through physical contact with another person.
Starfire is also an extremely proficient in armed and unarmed combat, having been trained in those arts by the Warlords of Okaara.