The invention discloses an integrated pin tool used for friction stir welding and a composite method of resistance-friction stir welding thereof. The pin tool comprises a pin tool body arranged on a friction welder and a tool pin arranged at the lower part of the tool pin body which is connected with the welder in a clamping and insulating manner; the pin tool also comprises a forced cooling system, a current carrying system, a gas shielding system, a temperature sensing and detecting system, a sealing and insulation system, an inner shaft shoulder and the tool pin, and is an integrated pin tool which has the functions of gas shielding, forced circulation cooling of internal liquid medium, automatic temperature sensing and detection, tool pin changing and composite non-keyhole resistance-friction stir welding. The invention overcomes the difficulty of friction stir welding of the high melting point metal and meets the harsh technical requirements of the friction stir welding of the low melting point metal, improves the quality of welding joints, prolongs the service life of the pin tool and realizes the friction stir welding of high melting point metal and low melting point light alloy, with low cost, high efficiency and excellent quality.