Assembly method of a photovoltaic panel with back-contact solar cells of crystalline silicon, which provides to print ECA adhesive directly on the contacts of the cells and to immediately load and pre-fix the printed cells. The method includes a macro-phase including operating sub-phases, simultaneous and coordinated with respect to each other: a first sub-phase of oriented loading of the cells with the contacts facing upwards on a mobile tray, a second sub-phase of silkscreen printing of ECA on the contacts, a third sub-phase of control of the laying carried out and of optional re-positioning of the screen, a fourth sub-phase of overturning of the printed cells, a fifth sub-phase of oriented transport of a string of cells up to positioning, a sixth sub-phase of pre-fixing. An automatic assembly plant is also disclosed having a combined station that allows for execution of the macro-phase.