The outstanding electrical and mechanical properties remain elusive on macroscopic carbon nanotube (CNT) films because of the difficult material process, which limits their wide practical applications. Herein, we report high-performance multifunctional MWCNT films that possess the specific electrical conductivity of metals as well as high strength. These MWCNT films were synthesized by a floating chemical vapor deposition method, purified at high temperature and treated with concentrated HCl, and then densified due to the developed chlorosulfonic acid-enhanced zipping effect. These large scalable films exhibit high electromagnetic interference shielding efficiency, high thermoelectric power factor, and high ampacity because of the densely packed crystalline structure of MWCNTs, which are promising for practical applications.