A film forming method, comprising circulating a first sputtering stage and a second sputtering stage until the thickness of a film satisfies a set requirement, wherein during the first sputtering stage and the second sputtering stage, a pulsed direct-current power is applied to a target; and increasing the density and stress of the thin film by setting a duty ratio of the pulsed direct-current power used in the first sputtering stage and a duty ratio of the pulsed direct-current power used in the second sputtering stage, respectively. The film forming method can achieve film deposition with a high density and a higher stress while ensuring process stability and a process cost.