Wolf Trap announced a summer season yesterday that includes a week of Lena Horne's Broadway show called "The Lady and Her Music," appearances by the Peking Circus and 2 1/2 weeks of the New York City Opera.

The season officially opens June 8 with the annual Wolf Trap Gala, which this year will introduce the New York City Opera's new production of Lehar's "The Merry Widow." That will run for six further performances.

The season will close with the return for two nights of Abel Gance's epic film, "Napoleon," which recently showed for two sellout weeks at the Kennedy Center.

Other special events will include Rodgers and Hammerstein's "The Sound of Music," with Roberta Peters and Theodore Bikel (a week in early September), the San Francisco Ballet (in late August) and a six-day jazz festival starring Ella Fitzgerald and Oscar Peterson.

The New York City Opera will return in late July with Verdi's "La Traviata" and "Rigoletto," Donizetti's "Lucia di Lammermoor" and Bizet's "The Pearl Fishers."

The Wolf Trap Company will present two important operatic novelties: Marc Blitzstein's "Regina," based on Lillian Hellman's "The Little Foxes," and "King Roger" by the Polish composer Karol Szymanowski, to observe the composer's 100th birthday. Richard Woitach will conduct both.

A two-day modern dance festival is being introduced for the first time, with four ensembles--Philadanco, Second Stride, the Rachel Harms Dance Company, and Nina Wiener & Dancers.

There will be 11 National Symphony Orchestra concerts. Three will be conducted by Mstislav Rostropovich (two of which will be all-Tchaikovsky programs). Hugh Wolff will conduct three others. The Symphony's soloists will include Andre' Watts, Andre'-Michel Schub, Horacio Gutie'rrez, Eugene Istomin, the Romeros and the Canadian Brass Ensemble. The American Philharmonic will come for one concert under Rohan Joseph, with pianist Malinee Peris.

Among the classical recital artists will be flutist Jean-Pierre Rampal, soprano Brenda Boozer and tenor Jon Vickers in a rare appearance.

Among the pop acts will be Lionel Hampton, Teddy Wilson, Louis Bellson, Milt Hinton, the Tex Beneke orchestra, Lou Rawls, Pete Seeger, Arlo Guthrie, Judy Collins, Ray Charles, Jane Olivor and the Roy Clark show.

The week-long jazz festival will begin June 15, with most performers still to be announced. There will also be a two-day "Bluegrass Bonanza" starting July 5.

Lena Horne will appear during the week of Aug. 3. The Peking Circus will be here from July 12 until July 15.