Multi-row in-line filling machine and filling method thereof

The multi-row in-line filling machine comprises a filling part, a first conveying part, a second conveying part and a pushing part, the first conveying part is arranged on one side of the filling part, the second conveying part is arranged on the other side of the filling part, and the conveying direction of the first conveying part is parallel to or perpendicular to the conveying direction of the second conveying part; at least one row and two columns of filling head assemblies are arranged on the filling part, the filling head assemblies are arranged in parallel, the first conveying part conveys a container to be filled, the second conveying part conveys the filled container, the pushing part pushes the container to be filled to the position below the filling head assemblies, the pushing part pushes the filled container to the second conveying part, and the first conveying part conveys the filled container to the second conveying part. In other words, every time the previous round of material filling is com