From LEGO Batman Wiki
She wears a Tiara which she is able to throw (Much like Batarangs). Star underpants, an Eagle emblem on her shirt and a W for her belt. She also carries the Lasso of Truth.
Diana is an Amazon from the island of Themyscira and her mother, Hippolyta, is their queen. As a baby, Diana was blessed with abilities by Greek Goddesses and Hermes (the only God who blessed her). A contest was held late where Diana was a woman to see who would help "Man's World" Diana won and left Themyscira to use her abilities to help people in "Man's world" as the super heroine Wonder Woman. Wonder Woman is also a member of the Justice League which also includes other super heroes such as Superman, Batman, Green Lantern, The Flash, Cyborg, Aquaman, Martian Manhunter, and occasionally Batgirl, Nightwing, Huntress, Zatanna, Hawkman, Hawkgirl and Shazam!. Wonder Woman occasionally helps out the of Birds of Prey, a team of superheroines.
In the consoles version, Wonder Woman is one of the Justice League members The Martian Manhunter is monitoring while he talks to Bruce Wayne. Later under Martain Manhunter's request, she arrives in Gotham and helps Superman hold Wayne Tower in place while it is being attacked by The Joker and Lex Luthor's robot untilGreen Lantern and The Flash repair the foundation. You can play as her on the last level as she helps Batman, Robin, Green Lantern, The Flash, and Cyborg finish off the robot. Her invisible jet also appears as the minikit model on the last level and may be used in the hub after all ten minikits are found. In the portable version, Wonder Woman is one of the Justice League members who arrive to help Batman and Superman defeat Lex Luthor outside Wayne Manor, you can play as her on the last level. She costs 100,000 studs. In LEGO Batman 2: DC Super Heroes, she is identical to her appearance in 6862 Superman vs. Power Armour Lex, except her lasso is more flexible. Wonder Woman has super strength, invincibility, a boomerang tiara (tiara-rang), can fly, and can use her Lasso of Truth to pull some grapple handles and to attack enemies. In the DS and 3DS games she dosn't have invincibility.