A suicide bomber was killed when the booby-trapped car she was driving blew up in the main square of the Christian southern Lebanese town of Jezzine today, injuring at least seven persons, police reported.

The National Syrian Social Party asserted responsibility for the operation. In a communique, the group identified the woman driver as Norma Abu Hassan, 26, a Christian school teacher from northern Lebanon, The Associated Press reported.

Today's bombing came one week after a member of the same group was involved in an abortive seaborne attack on Israel's northern coast. Two Israeli soldiers and four guerrillas were killed in an ensuing gunbattle after the guerrillas made a morning landing in a rubber dinghy.

Jezzine, with a population of about 40,000, is the largest Christian town bordering the Israeli-held security zone in southern Lebanon. The town is about 20 miles north of the Israeli border and is controlled by the Israeli-backed South Lebanon Army, a Christian militia. The town has served as a haven for Christian refugees driven southward by Druze and Moslem militias from the Chouf mountains and townships east of Sidon since the summer of 1983.

Ten minutes before the gray BMW driven by Hassan exploded at 11:45 a.m., the South Lebanon Army detonated another bomb-packed car in Jezzine and arrested its driver, security sources in south Lebanon said. Christian-controlled radio stations in Beirut identified the driver as Ali Hossnieh, who it said was a Syrian carrying forged identity papers, the AP reported.

Jezzine deputy Edmond Rizk condemned the bombing. "We are stunned by this regrettable incident in the heart of Jezzine in the main square and on its main street in the midst of houses and shops," he said. Security sources reached by telephone said several buildings, a pickup truck and another car were damaged.

Rizk appealed to the town's Christian and Moslem inhabitants to stand together against attempts to divide them.

The pro-Syrian group allegedly has carried out at least four of the 19 suicide attacks targeting Israeli and South Lebanon Army posts in the south since Israel pulled out most of its troops last year.

The surge in guerrilla operations in south Lebanon after a lull of several months follows the implementation of a Syrian-supported security plan for west Beirut and the deployment of elite Syrian forces alongside Lebanese soldiers.

The possibility of extending the security plan to the coastal highway linking Beirut to Sidon has raised fears among Palestinian guerrillas that a clampdown by Syrian troops would affect their movement between the refugee camps in south Lebanon and the Lebanese capital.