The invention discloses a high-voltage direct-current transmission line high-resistance grounding fault identification method based on distributed parameters. The method comprises the following steps that step 1, direct-current line current at a rectification station side and direct-current line current at an inversion station side are monitored in real time, if the condition (||IR|-|II||) I set is satisfied in continuous 3ms, the existence of a fault point in a high-voltage direct-current transmission line is judged, and then a step 2 is conducted; step 2, fault point residual voltage URFm is calculated at the rectification station side and fault point residual voltage UIFm at the inversion station side is calculated respectively, and if URFM>=0.1IdR, an in-zone high-resistance grounding fault is judged, and a protecting outlet t1 is delayed; if URFm< 0.1IdR, an in-zone metal fault is judged, and a protecting outlet t2 is delayed. According to the high-voltage direct-current transmission line high-resistance grounding fault identification method based on the distributed parameters, the fault point residual voltage when the high-voltage direct-current transmission line grounding fault occurs is compared with initial stable voltage when high-resistance grounding fault occurs, whether the high-resistance grounding fault occurs or not is judged, so that the protecting outlet is started, the protecting outlet is not influenced by transition resistance, the shortage of protection of motion rejection when the high-resistance grounding fault occurs in a current direct-current line is compensated, and the flexibility of protection motion is improved.