The adsorption structure of aqueous triblock copolymer polypropylene oxide-polyethylene oxide-polypropylene oxide, PPO-PEO-PPO, on the Si surface was studied using neutron reflectometer. It is found that PEO blocks formed the outer layer of the adsorbed PPO-PEO-PPO film, while PPO blocks formed the inner layer and served as the anchor blocks. The adhesion strength of adsorbed PPO-PEO-PPO copolymer film was evaluated using atomic force microscopy and scratch tests. The results revealed that the molecular structure of triblock copolymer had a considerable effect on the adhesion strength. The triblock copolymer with a longer PPO chain and a higher weight percentage of PPO exhibited stronger adhesion and better lubrication performance.