In episode 12 of the fifth season, Clark took Lana to the Crystal Castle, and then Lana learned her secret. Clark proposed to her. When Lex was chasing Lana, a truck crashed Lana's car. Lana was killed in a car accident, and later he went to Jor-El (Clark's biological father). Jor-El helped Clark rewind the time to the day before Lana died, and then something happened to Jonathan.

In episode 16 of the sixth season, on the wedding day of Lana and Lex, Lana designed to lock Chloe in the freezer of the wine cellar and hide behind the wine rack outside the door. Chloe called Clark, who took down the door and welded it with heat energy. Lana knew Clark's secret at this time, and Lex's father forced Lana to marry Lex (Lana knew why Clark gave up Lana), saying that if Lana didn't marry,

Season 6 episode 19, Clark goes to the tunnel to save lex. The tunnel is full of green kryptonite. When the tunnel collapsed, Lex left Clark and ran away. Chloe asked Lana when she knew there were meteorites in the tunnel. At this time, Chloe knew that Lana knew Clark's secret.