The invention discloses a cap and pin-type suspension insulator string and a surface conductivity calculation method, so as to improve accuracy of simulation, calculation and analysis on the insulation performance of the cap and pin-type suspension insulator string and improve the insulation performance of the cap and pin-type suspension insulator string. The cap and pin-type suspension insulator string comprises multiple serial cap and pin-type suspension insulators; each cap and pin-type suspension insulator comprises an umbrella-shaped insulation piece, an iron cap and a steel pin; the umbrella-shaped insulation piece comprises a cap-shaped head part and an umbrella body; the cap-shaped head part is arranged at the umbrella top of the umbrella-shaped insulation piece; the umbrella body and the cap-shaped head part are connected; along a direction from the umbrella edge of the umbrella body to the center of the umbrella body, a first umbrella rib, a second umbrella rib, a third umbrella rib and a fourth umbrella rib are sequentially arranged on the inner umbrella cover of the umbrella body at intervals in a surrounding mode; the first umbrella rib, the second umbrella rib, the third umbrella rib, the fourth umbrella rib and the umbrella body are coaxial; the first umbrella rib, the second umbrella rib, the third umbrella rib and the fourth umbrella rib extend along the axis of the umbrella body respectively; the iron cap sleeves the cap-shaped head part; and the steel pin is arranged in the umbrella-shaped insulation piece.