The invention discloses a manufacturing method of high-mechanical-strength sintered neodymium iron boron permanent magnets, which includes: firstly, utilizing rare-earth elements, iron, titanium, cobalt and boron iron alloy as raw materials and weighing the raw materials; secondly, mixing the weighed raw materials and disposing the same in a vacuum melting induction furnace, and preparing quick-hardened tablets by means of quick hardening process; thirdly, saturating the quick-hardened tablets to absorb hydrogen at the room temperature and dehydrogenating the same to prepare hydrogen decrepitation powder, then preparing magnetic powder by the hydrogen decrepitation powder through jet mill process; fourthly, molding the magnetic powder in an oriented manner, pressing to form magnets, disposing the magnets into a vacuum sintering furnace to be sintered in a vacuum environment, and performing tempering heat treatment to obtain blanks; and fifthly, machining the blanks, cleaning and removing oil, scouring to obtain high-mechanical-strength sintered neodymium iron boron permanent magnets with bending resistance strength not lower than 500MPa and impact toughness not lower than 7.5KJ / m2. By the manufacturing method, processing difficulty of the sintered neodymium iron boron permanent magnets is reduced greatly, application range of the sintered neodymium iron boron permanent magnets is broadened and economic potential thereof is high.