Baffle is an important part of petroleum tank mounted on tanker. Petroleum filled in tanker will slosh and impact tank wall when it subjects to external perturbations such as emergency brake etc, its center of gravity is changed when tanker drives on uneven road or in emergency braking. In order to reduce sloshing and impact on tank, baffles are fitted in the tank, but some unreasonable baffle structure often causes the baffle crack and even leakage of tank. This paper studies the structure design and arrangement of tank baffle which can reduce petroleum sloshing and impact on tank wall, improve stability and safety of tanker. Stress and strain of the innovated baffle and tank is analyzed on ANSYS, which verifies innovated baffle and tank is reasonable and correct.