Abstract: Objective The visualization of vector fields has become an important means for the expression of flowsin many different disciplines.In order to express a marine fluid flow's structure more clearly,based oncritical point theory,we present a new seeding point placement strategy and a new adaptive-step com-putation model.Considering a local cell's velocity and flow direction jointly with two degrees of free-dom,it adjusts the steps by using two parameters and realizes the step acceleration and decelerationaccording to the flow direction.For the placement of the global flow field streamlines,we also give anew streamline density adjustment strategy based on a smoothing window.Experimental analysis of aglobal ocean flow visualization shows that this algorithm better expresses the marine fluid flow struc-ture and suggests a reasonable placement of streamlines.