at 9 tonight, Channel 7 is offering a television-movie version of ''I Want to Live,'' the 1958 film that won a best-actress Oscar for Susan Hayward. In this version, the role of Barbara Graham, who was convicted of murder and executed in a San Quentin gas chamber in 1955, is being filled by Lindsay Wagner. The teleplay, written by Don M. Mankeiwicz and Gordon Cotler, is based on the screenplay by Nelson Gidding and Mr. Mankeiwicz, and on newspaper articles by Ed Montgomery and letters by Barbara Graham.

The point of the entire endeavor, apart from providing a juicy role for Miss Wagner, is not terribly clear. In a case involving the brutal murder of an elderly woman, Miss Graham was found guilty along with two gangsters, Emmett Perkins and Jack Santo, who were also executed. Another man, who turned state's witness, insisted that Barbara actually did the killing. She always denied her guilt. These dramatizations imply that she was convicted primarily because of a shabby past that included jail sentences, including one for perjury, and assorted forms of hustling.

In fact, no evidence has ever been produced to show conclusively that Miss Graham was innocent. But this teleplay persists with the assertion that she was being tried in court and in the press ''not for what she did but what she is.'' She was a woman out of work with a record. While this interpretation of her life is being formulated, a sympathetic woman journalist is being told by her cynical editor that ''we are all whores - only you're smart enough to work the right side of the street.''

In the end, we are left on one side with the sorely put-upon Miss Graham, trashy but decent, and on the other side with nasty cops and reporters, dedicated but rotten. The overall impact depends on how naive you want to be about this sort of thing. If nothing else, Miss Wagner's skillful performance is highly persuasive. David Lowell Rich was the director.

JOHN J. O'CONNOR