The invention belongs to the technical field of metal surface treatment and corrosion protection, and particularly relates to chromium-free pre-passivating liquid for hot-galvanized steel pipes. The chromium-free pre-passivating liquid is prepared from following components in percent by weight: 5%-10% of a film forming agent, 2%-4% of an oxidizing agent, 2%-4% of an organic corrosion inhibitor, 2%-4% of an inorganic rare earth corrosion inhibitor, 0.5%-2% of a water quality stabilizer, 0.5%-2% of a base material wetting agent and the balance water. A preparation method of the chromium-free pre-passivating liquid includes the steps that the film forming agent, the oxidizing agent, the inorganic rare earth corrosion inhibitor and the water quality stabilizer are dissolved in the water, the materials are stirred, then the organic corrosion inhibitor and the base material wetting agent are added, and the materials are evenly stirred. The chromium-free pre-passivating liquid does not contain chromium and other toxic and harmful substances, the high-temperature stability of tank liquor of the chromium-free pre-passivating liquid is good, the appearances of the pre-passivated hot-galvanized steel pipes are bright, the inner walls of the pre-passivated hot-galvanized steel pipes are well resistant to white rust, and the chromium-free pre-passivating liquid can replace chromic anhydridefor pre-passivating.