The high pressure resistance of high-strength ship plate and q345 plate depends on which thickness specification q345 is, and there are many steel grades of high-strength ship plate. Ship plates of 32kg class (yield strength of 315mpa) and above are all high-strength ship plates. According to the strength level, ship plates can be divided into ordinary strength ship plates (yield strength of 235mpa) and high-strength ship plates (yield strength of 315mpa and 355mpa respectively). And 390mpa) and ultra-high-strength ship plates (yield strength of 420mpa, 460mpa, 500mpa, 550mpa, 620mpa and 690mpa, respectively). The yield strength of q345 is 345mpa, and as the thickness of the steel plate increases, the yield strength requirement is reduced, that is, there is a thickness effect. There is no thickness effect for all levels of shipboard. the yield strength of high-strength ship plates of 36kg class (yield strength of 355mpa) and above is higher than that of q345 steel plates.