The invention discloses a power transmission line passage way attachment compensation cost calculation data storage system. The system comprises an attachment compensation cost data storage module, a power transmission line attribute data storage module and other data storage modules; the attachment compensation cost data storage module comprises an attachment standard unit price database, the power transmission line attribute data storage module comprises a power transmission line engineering database and a power transmission line basic database, the other data storage modules include a database of household registration information of house owners along the line and an affiliated administration region database, a relation is established for the database of the household registration information of the house owners along the line and the power transmission line engineering database through tower numbers, and a relation is established for the attachment standard unit price database and the power transmission line engineering database through the attachment numbers and the tower numbers. According to the system, the on-site data access operation strength of a manager is relieved, and the efficiency of power transmission line passage way attachment compensation cost calculation work can be improved.