The present application discloses a displacement filling method and a related device, the method comprising: at t  n‑2 moment, t  n‑1 moment and t  n The vehicle is recognized as the second vehicle by the point cloud of the first vehicle at all times; the t corresponding to the identification of the second vehicle  n Time point cloud data to obtain the relative displacement s between the second vehicle and the first vehicle  n ;according to the relative displacement s  n and fill in the displacement Δs to obtain the actual relative displacement s between the second vehicle and the first vehicle  n ’; filling displacement Δs is based on the corresponding t of the second vehicle  n‑2 Time point cloud data, t  n‑1 The relative displacement s between the second vehicle and the first vehicle obtained by point cloud data recognition at each moment  n‑2 , relative velocity v  n‑2 , relative displacement s  n‑1 and the relative velocity v  n‑1 obtained by the operation.  It can be seen that based on the relative displacement s  n‑2 , relative velocity v  n‑2 , relative displacement s  n‑1 and the relative velocity v  n‑1 , pre-computing t  n The filling displacement Δs that needs to be filled after point cloud data recognition at any time, using its relative displacement s  n The actual relative displacement s obtained by filling  n ’, reduce the delay difference and avoid the problem of inaccurate lag.