Welding method of vertical ladder for ship

The invention provides a welding method of a vertical ladder for a ship. The welding method is characterized by comprising the following steps: providing two ladder assemblies and a plurality of square steel pedals and uniformly inserting the square steel pedals in an equally spaced manner into the two ladder assemblies; fixing the ladder assemblies according to edging-on positions; carrying out pre-welding treatment on the ladder assemblies and the square steel pedals; welding the connections of the second inner side surfaces of the ladder assemblies and the plurality of square steel pedals and the connections of the first outer side surfaces of the ladder assemblies and the plurality of square steel pedals in a staggered welding manner; overturning the to-be-welded ladder assemblies andthe plurality of square steel pedals by 180 degrees, and welding the connections of the first inner side faces of the to-be-welded ladder assemblies and the plurality of square steel pedals and the connections of the second o