A flip chip package with an anti-floating structure includes a leadframe, a flip chip, and a plurality of solders. The leadframe includes a plurality of leads and a fastening part. At least one locking hole is formed on an upper surface of the fastening part. The flip chip includes an active surface, and at least one locking protrusion and a plurality of bumps formed on the active surface. The locking protrusion is correspondingly plugged into the locking hole to act as an anti-floating structure for the flip chip package. When the solders are used for connecting the bumps with the leads by reflowing, the anti-floating structure will prevent the flip chip from floating up, and the solders will not generate necking after reflowing.